Predictive biomarkers of response to immune checkpoint inhibitors in melanoma.

: Advanced melanoma has recently been transformed by the advent of immune checkpoint inhibitors. These agents have altered the prognosis of this disease from a median survival of <1 year to recent data showing a 5-year survival surpassing 50%. Combination regimens combining PD-1 and CTLA-4 blockade are associated with superior response and progression-free survival at the cost of increased toxicities.: In this review, we discuss the clinical and investigational utility of predictive biomarkers of immune checkpoint inhibitor treatment in melanoma. Topics include tumor-intrinsic biomarkers, tumor microenvironment biomarkers, and host characteristic biomarkers. We also discuss biomarkers of immune-related adverse events and how biomarkers may be used to personalize the selection of immune checkpoint inhibition in patients.: The decisions confronting oncologists when choosing treatment are increasing in complexity. Biomarkers may aid in these treatment decisions and are growing in importance.