This clinical trial is focused on studying a type of skin cancer called melanoma, specifically in cases where the cancer has spread to other parts of the body (metastatic) or cannot be removed by surgery (unresectable). The study is investigating the effectiveness of two treatments: nivolumab, which is already used to treat melanoma, and a combination of relatlimab and nivolumab. Nivolumab is a medication that helps the immune system fight cancer cells, and relatlimab is being studied for its potential to enhance this effect.

The purpose of the study is to compare how well patients do when treated with the combination of relatlimab and nivolumab versus nivolumab alone. Participants in the study will receive either the combination treatment or nivolumab by itself. The study is designed to be “double-blind,” meaning neither the participants nor the researchers know who is receiving which treatment, to ensure unbiased results. Some participants may receive a placebo, which is a substance with no active medication, to help compare the effects of the treatments being studied.

Throughout the study, participants will receive their assigned treatment through an infusion, which is a way of delivering medication directly into the bloodstream. The study will monitor how long participants live without their cancer getting worse, known as progression-free survival. Other aspects, such as overall survival and the response of the cancer to the treatment, will also be observed. The study aims to provide valuable information on whether the combination of relatlimab and nivolumab offers better outcomes for patients with advanced melanoma compared to nivolumab alone.