Therefore, we analyzed plasma samples of 121 patients with melanoma treated at the Essen Department of Dermatology with either first-line dual ICI (anti-CTLA-4 plus anti-PD-1 antibodies, n = 70) or with first-line anti-PD-1 monotherapy (n = 51) (Fig. 5a,f). This evidence concerns the gene PDCD1 and melanoma.