Furthermore, the expression of ICIs between high- and low-risk melanoma patients were analyzed, indicating that the expression of immune-regulatory proteins (IRPs) such as PD-1 (PDCD1), PD-L1 (CD274), CTLA-4, HAVCR2 (TIM3), CD8, and LAG3 was significantly lower in the high-risk group (p < 0.05) (Figure 9E–J). Here, CTLA4 is linked to melanoma.