The purpose of this study is to learn about the effects of three study medicines (encorafenib, binimetinib, and pembrolizumab) given together for the treatment of melanoma that: * is advanced or metastatic (spread to other parts of the body); * has a certain type of abnormal gene called "BRAF"; and * has not received prior treatment. All participants in this study will receive pembrolizumab at the study clinic once every 3 weeks as an intravenous (IV) infusion (given directly into a vein). In addition, half of the participants will take encorafenib and binimetinib orally (by mouth) at home every day. Participants may receive pembrolizumab for up to two years. Those participants taking encorafenib and binimetinib can continue until their melanoma is no longer responding. The study team will monitor how each participant is doing with the study treatment during regular visits at the study clinic.