PDCD1 and hepatocellular carcinoma: The analysis result pointed out that risk signature had close relationship with CD274 (r = 0.2; p = 9.2e − 05), CTLA4 (r = 0.15; p = 0.0029), HAVCR2 (r = 0.21; p = 5.3e − 05), PDCD1 (r = 0.19; p = 0.00024), and PDCD1LG2 (r = 0.22; p = 2.1e − 05; Figures 6H–L), indicating risk signature might exert a nonnegligible player in ICB treatment outcome prediction in HCC.