A Study Comparing 3 Study Medicines (Encorafenib, Binimetinib, Pembrolizumab) to 2 Study Medicines (Ipilimumab and Nivolumab) in Patients With Advanced Melanoma

The purpose of this study is to learn about the effects of 3 study medicines (encorafenib, binimetinib, pembrolizumab) compared to 2 study medicines (ipilimumab and nivolumab) given for the treatment of melanoma. Melanoma is a type of cancer that starts in the cells that give color to your skin. The study is seeking participants who: * have advanced or metastatic melanoma (has spread to other parts of the body); * have a certain abnormal gene called "BRAF". * have taken nivolumab or pembrolizumab treatment before this study. Participants will either receive: * pembrolizumab given by intravenous infusion (directly into a vein) every 3 weeks at the study clinic. Participants will also receive encorafenib and binimetinib by mouth every day at home, * or will receive ipilimumab and nivolumab given by intravenous infusion (directly into a vein) every 3 weeks at the study clinic 4 times. This will be followed by nivolumab given by intravenous infusion every 4 weeks at the study clinic. Both pembrolizumab and nivolumab will be given for a maximum of around 2 years. However, there is no time limit for encorafenib and binimetinib treatment. The study team will see how each participant is doing after receiving the study treatments during regular visits to the study clinic.

The purpose of the study is to compare the efficacy of a triplet therapy (encorafenib, binimetinib, pembrolizumab) versus a doublet/control therapy (nivolumab and ipilimumab). Participants will have metastatic or unresectable locally advanced BRAF V600E/K-mutant melanoma, which progressed during or after prior treatment in the adjuvant or first-line metastatic setting, with an approved anti-PD-1 monotherapy (pembrolizumab or nivolumab), Approximately 150 participants will be randomized in a 1:1 ratio to the triplet or the doublet/control therapy (75 participants in each arm). Randomization will be stratified by baseline serum LDH level, and by type of PD-1 resistance.