Participants in this treatment arm must have a positive tumor biomarker result for human epidermal growth factor receptor 2 (HER2) mutations or amplification without known TMB high or MSI high/dMMR.

Participants in this treatment arm must have a positive tumor biomarker result for HER2 mutation or amplification without known TMB high or MSI high/dMMR.

Participants in this treatment arm must have a positive tumor biomarker result for HER2 mutation or amplification without known TMB high or MSI high/dMMR.

Participants in this treatment arm must have a positive tumor biomarker result for HER2 mutation or amplification without known TMB high or MSI high/dMMR.

Participants in this treatment arm must have positive tumor biomarker results for HER2 mutation or amplification and TMB high or MSI high/dMMR.

Participants in this treatment arm must have a positive tumor biomarker result for PI3KCA activating mutation.

Participants in this treatment arm must have a positive tumor biomarker result for either AKT1/2/3 activating mutation or PTEN loss/loss of function.

Participants in this treatment arm must have a positive tumor biomarker results for PI3KCA activating mutations and either AKT1/2/3 activating mutation or PTEN loss/loss of function.

Participants in this treatment arm must have a positive tumor biomarker result for either TMB high or MSI high/dMMR.

Participants in this treatment arm must have a positive tumor biomarker result for RET fusion.

Inavolisib will be self-administered by participants orally at home (except on clinic days) at the same time each day, on a starting dose of 9 mg/day QD until disease progression, intolerable toxicity, or consent withdrawal.

Alectinib will be self-administered by participants orally at home (except on clinic days), at the same times each day, on a starting dose of 600 mg twice a day (BID) until disease progression, intolerable toxicity, or consent withdrawal.

Ipatasertib will be self-administered by participants orally at home (except on clinic days), at the same time each day, on a starting dose of 400 mg QD until disease progression, intolerable toxicity, or consent withdrawal.

Atezolizumab will be administered by intravenous (IV) infusion at a fixed dose of 1200 mg for participants on Day 1 of each 21-day cycle until unacceptable toxicity or progressive disease (or loss of clinical benefit).

Trastuzumab emtansine will be administered at 3.6 mg per kilogram (kg) of body weight by IV infusion every 21 days (unless dose reduction and/or dose delays are required) until disease progression or unacceptable toxicity.

PH FDC SC will be administered subcutaneously (SC) at a fixed non-weight-based dose. A loading dose of 1200 mg SC pertuzumab and 600 mg SC trastuzumab is then followed by a maintenance dose of 600 mg SC pertuzumab and 600 mg SC trastuzumab once every 3 weeks.

Tucatinib 300 mg will be administered orally BID continuously starting from Cycle 1 Day 1 onwards.

Chemotherapy will consist of docetaxel, paclitaxel, or capecitabine, as determined by the investigator, and will be administered per the respective package insert and institutional guidelines.

The dose of paclitaxel is 80 mg/m2 administered by IV infusion on Days 1, 8, and 15 of each 28-day cycle. The paclitaxel infusion will be delivered over at least 60 minutes for each dose per institutional guidelines and administered after the oral dose of ipatasertib.

Following the administration of atezolizumab and an observation period, participants will receive 600 mg tiragolumab at a fixed dose administered by IV infusion on Day 1 of each 21-day cycle.

Pralsetinib will be self-administered by participants orally at home (except on clinic days), at the same time each day, on a starting dose of 400 mg/day (four 100-mg capsules per day) once a day (QD) until disease progression, intolerable toxicity, or consent withdrawal.

DOR was defined as the time from the date of the first confirmed complete response (CR) or partial response (PR) to disease progression (PD) or death from any cause, whichever occurs first, as determined by the investigator according to RECIST v1.1 or RANO. CR & PR were defined per RECIST or RANO as outlined in the description for the cORR outcome measure (OM). PD was defined per RECIST or RANO as outlined in the description for the PFS OM. Kaplan-Meier methodology was used to estimate the median DOR. The 95% confidence intervals for the median DOR were computed by the method of Brookmeyer and Crowley. Participants who did not experience death or PD were censored on the day of the last available assessment.

The PFS rates were calculated using the Kaplan-Meier (KM) method to estimate the percent survival probability of participants (i.e., PFS event-free: did not experience PD or death from any cause) in each treatment arm at landmark timepoints. The 95% confidence intervals for each PFS rate were computed by the method of Greenwood. PFS was defined as the time from the start of study treatment to the first occurrence of PD or death from any cause, whichever occurs first, as determined by the investigator according to RECIST v1.1 or RANO. PD was defined per RECIST or RANO as outlined in the description for the PFS OM. Participants who did not experience death or PD were censored on the day of the last available assessment. The number analyzed per landmark timepoint actually represents the number of participants who remained at risk of experiencing a PFS event at that timepoint. Percentages are rounded off to the nearest decimal point.

Disease control rate was defined as the percentage of participants whose best response was confirmed CR, confirmed PR, or a response of CR, PR, stable disease (SD), or non-CR/non-PD for a minimum of 98 days for 28-day cycle arms or 70 days for 21-day cycle arms after the first treatment date. CR & PR were defined per RECIST/RANO as outlined in the description for the cORR OM. SD per RECIST: Neither sufficient shrinkage to qualify for CR or PR nor sufficient increase to qualify for PD. SD per RANO: Participant does not qualify for CR, PR, or minor response or PD; Stable non-enhancing (T2/FLAIR) lesions or abnormalities on same or lower dose of corticosteroids compared to baseline; No new lesions or new T2 or FLAIR abnormalities apart from those consistent with radiation effect, & no new or increased enhancement; Participants on a should be corticosteroid dose that is not greater than dose at baseline scan & is stable or improved clinically; Clinical status, stable/improved.

An AE is an untoward medical occurrence in participant administered a pharmaceutical product & regardless of causal relationship with the product. An AE can therefore be any unfavorable & unintended sign (including an abnormal laboratory finding), symptom/disease temporally associated with use of investigational product, whether or not considered related to it. AEs were graded for severity according to NCI CTCAE v5.0. Grade 1= Mild; asymptomatic or mild symptoms; clinical or diagnostic observations only; or intervention not indicated; Grade 2=Moderate; minimal, local or non-invasive intervention indicated; or limiting age-appropriate instrumental activities of daily living; Grade 3 = Severe or medically significant, but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; or limiting self-care activities of daily living; Grade 4= Life-threatening consequences/urgent intervention indicated; Grade 5= Death related to adverse event.

Participants with a positive tumor biomarker result for phosphatase and tensin homolog (PTEN) loss/loss-of-function or protein kinase B (AKT) activating mutation self-administered ipatasertib, 400 mg orally, QD until disease progression, intolerable toxicity, or consent withdrawal, whichever occurs first.

Participants with a positive tumor biomarker result for tumor mutational burden-high (TMB-H) or microsatellite instability high (MSI-H) or deficient mismatch repair (dMMR) received atezolizumab,1200 mg, as intravenous (IV) infusion, on Day 1 of each 21-day cycle in combination with investigators choice of chemotherapy (docetaxel, paclitaxel, or capecitabine) until disease progression, loss of clinical benefit, or unacceptable toxicity whichever occurs first.

Participants with a positive tumor biomarker result for human epidermal growth factor receptor 2 (HER2) gene amplification or mutation without known TMB-H/ MSI-H/ dMMR received atezolizumab, 1200 mg, as IV infusion, on Day 1 of each 21-day cycle, followed by trastuzumab emtansine, 3.6 milligrams/kilograms (mg/kg), as IV infusion, every 21 days until disease progression, loss of clinical benefit, or unacceptable toxicity, whichever occurs first.

Participants with a positive tumor biomarker result for HER2 gene amplification or mutation without known TMB-H/ MSI-H/ dMMR received PH FDC SC, a loading dose of 1200 mg pertuzumab + 600 mg trastuzumab as subcutaneous (SC) injection on Day 1 of Cycle 1 followed by a maintenance dose of 600 mg pertuzumab + 600 mg trastuzumab as a SC injection on Day 1 of each 21-day cycle, starting at Cycle 2.

Participants with a positive tumor biomarker result for HER2 gene amplification or mutation without known TMB-H/ MSI-H/ dMMR received PH FDC SC, a loading dose of 1200 mg pertuzumab + 600 mg trastuzumab as a SC injection on Day 1 of Cycle 1 followed by a maintenance dose of 600 mg pertuzumab + 600 mg trastuzumab as a SC injection on Day 1 of each 21-day cycle, starting at Cycle 2 in combination with investigators choice of chemotherapy (docetaxel, paclitaxel, or capecitabine).

Participants with a positive tumor biomarker result for HER2 gene amplification or mutation without known TMB-H/ MSI-H/ dMMR received trastuzumab emtansine, 3.6 mg/kg as IV infusion, every 21 days in combination with tucatinib, 300 mg, orally, BID starting from Cycle 1 Day 1 until disease progression or unacceptable toxicity, whichever occurs first.

Participants with a positive tumor biomarker result for HER2 gene amplification or mutation plus TMB-H/ MSI-H/ dMMR received atezolizumab, 1200 mg, as IV infusion, on Day 1 of each 21-day cycle, followed by trastuzumab emtansine, 3.6 mg/kg, as IV infusion, every 21 days until disease progression, loss of clinical benefit, or unacceptable toxicity, whichever occurs first.

Participants with a positive tumor biomarker result for PIK3CA activating mutation received ipatasertib, 400 mg, orally QD in combination with atezolizumab, 1200 mg, as IV infusion, on Day 1 of each 21-day cycle until disease progression, loss of clinical benefit, or unacceptable toxicity, whichever occurs first.

Participants with a positive tumor biomarker result for PTEN loss/loss-of-function or AKT-activating mutation self-administered ipatasertib, 400 mg, orally, QD and received atezolizumab, 1200 mg, as IV infusion, on Day 1 of each 21-day cycle until disease progression, loss of clinical benefit, or intolerable toxicity, whichever occurs first.

Participants with a positive tumor biomarker result for co-mutations in PIK3CA activating mutations and PTEN loss/loss-of-function or AKT-activating mutation self-administered ipatasertib, 400 mg, orally, QD on Days 1 to 21 of 28-day cycles and received paclitaxel, 80 milligrams per meter square (mg/m^2), as IV infusion on Days 1, 8, and 15 of each 28-day cycle until disease progression, intolerable toxicity, or consent withdrawal, whichever occurs first.

Participants with a positive tumor biomarker result for TMB-H/ MSI-H/ dMMR received atezolizumab, 1200 mg, as IV infusion, on Day 1 of each 21-day cycle, followed by tiragolumab, 600 mg, as IV infusion on Day 1 of each 21-day cycle until disease progression, loss of clinical benefit, or unacceptable toxicity, whichever occurs first.

Participants with a positive tumor biomarker result for rearranged during transfection (RET) gene fusion self-administered pralsetinib, 400 mg, orally, QD until disease progression, intolerable toxicity, or consent withdrawal whichever occurs first.