Single cell RNA-seq revealed similar gene expression signatures that were also found in mice, i.e., PDCD1, GZMB, TOX, CXCR6, RGS1, and SELL. Furthermore, a meta-analysis of three large randomized controlled phase III trials of immunotherapies in patients with advanced HCC, namely Checkmate-495, IMbrave150, and Keynote-240 [15,16,21], showed that anti-PD-1 or anti-PD-L1 treatment in the control arm led to superior outcome in patients with HBV- and HCV-related HCC, but not in patients with non-viral HCC. This evidence concerns the gene RGS1 and hepatocellular carcinoma.