IDO1 and cutaneous melanoma: Additionally, we showed that cutaneous melanoma patients with ARID1A mutation were enriched in high expression levels of immune checkpoint infiltration genes, such as PDCD1LG2 and IDO1. Despite a comparatively high prevalence of TMB and total neoantigen load in all ARID mutated cutaneous melanoma patients, those with ARID1A fail to demonstrate a significant increase in IFN-γ score or enrichment in CD274, potential markers for ICI therapy response, when compared to WT patients.