The Gut Microbiome and Immunotherapy Response in Solid Cancers

Inclusion Criteria: 1. Current diagnosis of malignant solid cancer that is nonresectable or metastatic. 2. Ages 35 to 75 years. 3. Treatment with immunotherapy, specifically programmed cell death protein 1 (PD-1) or programmed cell death ligand 1 (PD-L1) inhibitor, for at least 3 months but less than 24 months (except for previously responsive subjects re-enrolling as non-responsive patients). 4. Measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 guidelines. 5. Participant is willing and able to give informed consent for participation in the study Exclusion Criteria: 1. Significant heart, liver, blood or respiratory disease. 2. Current diagnosis of HIV, Hepatitis B or Hepatitis C. 3. History of heart disease. 4. Uncontrolled diabetes mellitus. 5. Subjects with a history of inflammatory bowel disease, Celiac disease or active diverticular disease. 6. Females who are pregnant or lactating. 7. Treatment with chemotherapy within the past 2 years. 8. Treatment with kinase inhibitors within the past 3 months. 9. Previous radiation therapy for brain metastases. 10. Other medical condition or medication administration deemed exclusionary by the study investigators.