Therefore, we analyzed six key immune checkpoint inhibitor genes (HAVCR2, CTLA‐4, PDCD1, PDCD1LG2, IDO1, and CD274) in an HCC cohort (Kanehisa et al., 2017; Ye et al., 2021; Zhu et al., 2021). Here, CTLA4 is linked to hepatocellular carcinoma.