STAT1 was significantly positively correlated with PD1 (r = 0.448), PD-L1 (r = 0.444), CTLA-4 (r = 0.436), FGFR2 (r = 0.354), FGFR3 (r = 0.36), and IDO1 (r = 0.387) in HCC, suggesting that targeting STAT1 may improve the efficacy of immunotherapy for hepatocellular carcinoma. Here, IDO1 is linked to hepatocellular carcinoma.