PDCD1 and melanoma: Cohort 1 consisted of 88 patients treated with anti-PD-1 monotherapy (n = 47, including pre-treatment [PRE] samples, n = 38, and early during therapy [EDT] samples, n = 9) or combined anti-CTLA-4 and anti-PD-1 therapy (patients, n = 41, including PRE, n = 32 and EDT, n = 9; Supplementary Data 1), while Cohort 2 consisted of 69 melanoma patients undergoing anti-PD-1 therapy (nivolumab or pembrolizumab) (Supplementary Data 2).