IDO1 and melanoma: An IFN-γ-related mRNA profile that contains 10 genes (CCR5, CXCL9, CXCL10, CXCL11, GZMA, HLA-DRA, IDO1, IFNG, PRF1, and STAT1) was additionally identified to predict the response to anti-PD-1 therapy in melanoma (87).