1. Phase 1b: Histologically and/or cytologically confirmed metastatic selected solid tumor types that have progressed after treatment with approved therapies or for which there are no standard effective therapies available. If nivolumab or pembrolizumab is an approved therapy for the participant's tumor type, but the participant has not been treated with it, the Investigator may enroll the participant in this study. Phase 2: Histologically and/or cytologically confirmed metastatic selected solid tumor types with 0-2 prior lines of systemic therapy (unless discussed with the sponsor) For the non-small cell lung cancer (NSCLC) and melanoma cohorts, participants must have progressed on or after prior treatment with one anti-PD-1, anti-PD-L1, or anti-PDL2 agent Selected tumor types of both phases: NSCLC, predominantly clear cell renal cell carcinoma, endometrial carcinoma, urothelial carcinoma, squamous cell carcinoma of the head and neck, or melanoma (excluding uveal melanoma)