Immune checkpoint inhibitors, such as human anti-PD-1 monoclonal antibodies (nivolumab and pembrolizumab) and human anti-CTLA4 monoclonal antibody (ipilimumab), were approved for advanced HCC from 2017 to 2020, which greatly extend the patients’ overall survival [13,14,15]. The gene discussed is CTLA4; the disease is hepatocellular carcinoma.