For more information regarding Bristol-Myers Squibb Clinical Trial participation, please visit www.BMSStudyConnect.com Inclusion Criteria: - Refractory, metastatic, or unresectable TMB-H solid tumors who must have received at least one prior line of therapy including standard of care, if available - Available tumor tissue and blood for TMB testing - Participants must have measurable disease for response assessment Exclusion Criteria: - Participants with melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC) or hematological malignancy as primary site of disease - Participants who received prior treatment with an anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137, or anti-CTLA-4 antibody, or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways - Treatment with any chemotherapy, radiation therapy, biologics for cancer, or investigational therapy within 28 days of first administration of study treatment Other protocol defined inclusion/exclusion criteria could apply