This is a Phase 1, single-dose, open-label, dose-escalation study. The study will be conducted in three parts (i.e. regimens) in an outpatient setting as follows:

• Regimen A: FATE-NK100 as a monotherapy in subjects with advanced solid tumor malignancies.
• Regimen B: FATE-NK100 in combination with trastuzumab in subjects with human epidermal growth factor receptor 2 positive (HER2+) advanced breast cancer, HER2+ advanced gastric cancer or other advanced HER2+ solid tumors.
• Regimen C: FATE-NK100 in combination with cetuximab in subjects with advanced colorectal cancer (CRC) or head and neck squamous cell cancer (HNSCC), or other epidermal growth factor receptor 1 positive (EGFR1+) advanced solid tumors.

Inclusion Criteria:

1. Regimen A only (monotherapy): Subjects with advanced metastatic solid tumors
2. Regimen B only (combination with trastuzumab): Subjects with advanced metastatic HER2+ solid tumors
3. Regimen C only (combination with cetuximab): Subjects with advanced metastatic EGFR+ solid tumors
4. Available related donor who is CMV+ and HLA-haploidentical or better but not fully HLA-matched
5. Presence of measurable disease by RECIST 1.1
6. Life expectancy of at least 3 months.
7. Provision of signed and dated informed consent form (ICF).
8. Stated willingness to comply with study procedures and duration.

Exclusion Criteria:

1. Females of reproductive potential that are pregnant or lactating, and males or females not willing to use a highly effective form of contraception from Screening through the end of the study.

2. Eastern Cooperative Oncology Group (ECOG) performance status >2.

3. Evidence of insufficient organ function as determined by the protocol.

4. Receipt of any biological therapy, chemotherapy, or radiation within 1 week of the Screening Visit and at least 3 weeks prior to Day 1, except for patients receiving maintenance trastuzumab.

5. Have central nervous system disease (CNS) as follows:

   1. Dose Escalation Cohorts: Active CNS disease, including history of CNS metastases.
   2. MTD/MFD Expansion Cohorts: CNS disease, including history of CNS metastases, that was not stable during the last 6 months.

6. Myocardial infarction (MI) within 6 months of Screening Visit.

7. Severe asthma.

8. Currently receiving or likely to require systemic immunosuppressive therapy from Day -7 to Day 29.

9. Uncontrolled infections.

10. Presence of any medical or social issues that are likely to interfere with study conduct, or may cause increased risk to subject.