The most studied immune checkpoints in HCC includes cytotoxic T lymphocyte protein 4 (CTLA-4), programmed cell death protein-1 and its ligand (PD-1, PD-L1), lymphocyte activation gene 3 protein (LAG-3) and mucin domain-containing molecule-3 (Tim-3). The gene discussed is CTLA4; the disease is hepatocellular carcinoma.