Historically, metastatic melanoma has been associated with a poor prognosis. Recently, numerous immunotherapeutic agents, particularly checkpoint inhibitors, have moved to the forefront of therapy. Checkpoint inhibitors such as ipilimumab, pembrolizumab, and nivolumab have revolutionized the treatment of melanoma. Despite this, not all patients respond to checkpoint inhibitors, and even patients who initially respond to checkpoint inhibitor therapy often later relapse (median response duration of 2 years); complete responses remain uncommon. Thus, more effective immunotherapies are clearly needed.