To confirm the value of these four subsets of immune cells in the prognosis of malignant melanoma treated with PD-1 blockade, we applied it to the independent validation set of 73 advanced melanoma patients treated with anti-PD-1 monotherapy (n = 41) or combined anti-PD-1 and anti-CTLA-4 (n = 32) (25). This evidence concerns the gene CTLA4 and melanoma.