Inclusion Criteria: - Must have documented progression while on a prior anti-programmed cell death protein 1 (PD-1) containing regimen. - Women of childbearing potential (WOCBP) must have a negative serum or urine pregnancy test - Participants must have histologically confirmed advanced unresectable (Stage III) or metastatic (Stage IV) melanoma, as per AJCC staging system - Tumor tissue from an unresectable or metastatic site of disease must be provided for biomarker analyses. - BRAF wild type and mutant participants are eligible - Eastern Cooperative Oncology Group (ECOG) 0-1 - Ability to comply with treatment, patient-reported outcomes (PROs), PK, and pharmacodynamic sample collection and required study follow-up Exclusion Criteria: - History of uveal melanoma - Known history of positive test for human immunodeficiency virus (HIV) or known acquired immunodeficiency syndrome - Prior treatment with ipilimumab, relatlimab, or any other CTLA-4 or LAG-3 targeted agents - Positive blood screen for hepatitis C antibody, hepatitis B surface antigen, or HIV-1 and HIV-2 antibody.