CTLA4 and hepatocellular carcinoma: We observed that the risk score had significantly positive correlation with CD274 (r = 0.2; P = 1e−04; Figure 6J), CTLA4 (r = 0.17; p = 0.0014; Figure 6K), HAVCR2 (r = 0.24; p = 2.4e−06; Figure 6L), IDO1 (r = 0.13; p = 0.014; Figure 6M), and PDCD1LG2 (r = 0.11; p = 0.031; Figure 6N), suggesting the risk prognostic signature might play a crucial role in the monitoring of the ICB therapy outcome in patients with HCC.