A Study to Evaluate the Safety and Tolerability of BMS-986408 Alone and in Combination With Nivolumab or Nivolumab and Ipilimumab in Participants With Advanced Solid Tumors

The primary purpose of this study is to characterize the safety profile of BMS-986408 as monotherapy and in combination with nivolumab or nivolumab and ipilimumab to establish the maximum tolerated dose (MTD). The Recommended Phase 2 Dose (RP2D) that optimizes the pharmacokinetic/pharmacodynamic (PK/PD) relationship of BMS-986408 will also be determined.

Inclusion Criteria: * Participants with a histologically or cytologically confirmed, advanced, unresectable/metastatic, solid malignancy of any histology measurable by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 * Participants who have received, been refractory to, ineligible for, or intolerant of existing therapy(ies) known to provide clinical benefit for the condition of the participant * Participants with melanoma should have documentation of mutation status for B-type Raf proto-oncogene (BRAF) and neuroblastoma ras viral oncogene homolog (NRAS) * Participants must have experienced radiographically documented progressive disease on or after the most recent therapy Exclusion Criteria: * An active, known or suspected autoimmune disease * Conditions requiring systemic treatment with either corticosteroids within 14 days or other immunosuppressive medications within 30 days of the first dose of study treatment * Current or recent gastrointestinal disease or gastrointestinal surgery that could impact the absorption of study drug * Untreated central nervous system (CNS) metastases or leptomeningeal metastasis Other protocol-defined inclusion/exclusion criteria apply