A Study To Assess the Safety, and Tolerability of Nivolumab + Relatlimab Fixed-Dose Combination (FDC) In Untreated, Unresectable or Metastatic Melanoma Participants In India

Inclusion Criteria * Participants must have an Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1/Lansky Performance Score ≥ 80% for minors (ages 12-17) ONLY. * Participants must have histologically confirmed Stage III (unresectable) or Stage IV melanoma, per the American Joint Committee on Cancer (AJCC) staging system (8th edition). * Participants must be treatment-naïve (ie, no prior systemic anticancer therapy for unresectable or metastatic melanoma). * Participants must have measurable disease by Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 criteria. * Participants must have completed prior radiotherapy at least 2 weeks prior to study treatment administration. * Individuals of Childbearing Potential (IOCBP) must not be pregnant or breastfeeding. Exclusion Criteria * Participants must not have active brain metastases or leptomeningeal metastases. * Participants must not have uveal melanoma. * Participants must not have an active, known, or suspected autoimmune disease. * Participants must not have a condition requiring systemic treatment with either corticosteroids (\> 10 mg daily prednisone equivalent) or other immunosuppressive medications within 14 days of start of study treatment. * Participants must not have a history of myocarditis. * Participants must not have had prior treatment with an anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CTLA-4 antibody, or any other antibody or drug specifically targeting T-cell costimulation or immune checkpoint pathways. Prior treatment with relatlimab or any other with LAG-3 targeted agents. * Other protocol-defined Inclusion/Exclusion criteria apply.