CTLA4 and hepatocellular carcinoma: Programmed cell death receptor-1 and ligand-1 (PD-1/ PD-L1) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) operate via complementary immunosuppressive signaling pathways, and a combined regimen to inhibit both pathways may improve outcomes in cases of advanced HCC.