CTLA4 and hepatocellular carcinoma: Recent advances in immune checkpoint inhibitors (ICIs), including programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), have shown promise for improving the prognosis of patients with hepatocellular carcinoma (HCC).