Targeting immune checkpoint pathways in melanoma: triumphs and challenges

The immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced melanoma by significantly increasing survival rates, with the promise of durable disease remission in some patients. Herein we review the role of immune checkpoints in melanoma; the history of melanoma immunotherapy; pivotal clinical trial data for ipilimumab, pembrolizumab, nivolumab and relatlimab; and the current clinical role of each ICI. We discuss the challenges that accompany these triumphs in the treatment of melanoma, including: how to distinguish between responders and nonresponders; how to optimize ICI dosing and combinatorial approaches; and the best practices for monitoring response and managing immune-related toxicities. We offer our perspective on the financial toxicity of ICIs and new developments that could deliver answers to current challenges.