A Study to Assess Adjuvant Immunotherapy With Nivolumab Plus Relatlimab Versus Nivolumab Alone After Complete Resection of Stage III-IV Melanoma

Inclusion Criteria:

Must have been diagnosed with either Stage IIIA (> 1 mm tumor in lymph node)/B/C/D or Stage IV melanoma by American Joint Committee on Cancer (AJCC) v8 and have histologically confirmed melanoma that is completely surgically resected (free of disease) with negative margins in order to be eligible
Participants ≥ 18 years of age must have an Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1. Adolescent participants between 12 and < 18 years of age must have a Lansky/Karnofsky performance score ≥ 80%
Complete resection must be performed within 90 days prior to randomization
All participants must have disease-free status documented by a complete physical examination within 14 days prior to randomization and imaging studies within 35 days prior to randomization
Tumor tissue must be provided for biomarker analyses

Exclusion Criteria:

History of ocular melanoma
Untreated/unresected CNS metastases or leptomeningeal metastases
Active, known, or suspected autoimmune disease
Participants with serious or uncontrolled medical disorder
Prior immunotherapy treatment for any prior malignancy: No prior immunotherapies are permitted
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection within 4 weeks prior to screening
History of myocarditis, regardless of etiology.

Other protocol-defined inclusion/exclusion criteria apply