Melanoma patients (pts) who received anti-CTLA-4 (ipilimumab), anti-PD-1 (pembrolizumab or nivolumab), or the combination at the Center for Immuno-Oncology and Melanoma at DFCI in the past 5 years (up to December 31- 2016) were included. Here, PDCD1 is linked to melanoma.