Study terminated due to strategic business decision by Eli Lilly and Company.

The purpose of this study is to evaluate the safety of the study drug LY3381916 administered alone or in combination with anti-programmed cell death ligand 1 (PD-L1) checkpoint antibody (LY3300054).

Inclusion Criteria:

• Dose escalation phase: Participant must have histological or cytological evidence of a diagnosis of cancer that is advanced and/or metastatic.
• Dose expansion B1: Metastatic TNBC participants who have not received prior PD-1/L1 treatment.
• Dose expansion B2: Metastatic NSCLC participants who have progressed on prior PD-L1/L1 treatment.
• Dose expansion B3: Metastatic clear cell carcinoma RCC who have progressed on prior PD-L1/L1 treatment.
• Have adequate organ function.
• Have a performance status (PS) of ≤1 on the Eastern Cooperative Oncology Group (ECOG) scale.
• Are able and willing to provide required, newly acquired tumor biopsies.
• Have discontinued previous treatments for cancer.
• Are able to swallow capsules.

Exclusion Criteria:

• Currently enrolled in a clinical study.
• Have known symptomatic central nervous system metastases or carcinomatous meningitis.
• Have a serious concomitant systemic disorder.
• Have a symptomatic human immunodeficiency virus infection or symptomatic activated/reactivated hepatitis B or C.
• Have a significant cardiac condition.
• Have previously received an indoleamine- 2,3-dioxygenase (IDO) inhibitor.
• Have an active autoimmune disease or currently require immunosuppression of >10 milligrams of prednisone or equivalent per day.
• Have interstitial lung disease or (noninfectious) pneumonitis, participants with a history of (noninfectious) pneumonitis that required steroids to assist with management.