PDCD1 and hepatocellular carcinoma: Multikinase inhibitors (MKIs) (sorafenib, regorafenib, and lenvatinib), tyrosine kinase inhibitors (TKIs) (cabozantinib), and the immune checkpoint blockade (ICB) therapy to target cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed cell death-1 and its ligand (PD-1/PD-L1) have opened up possibilities for immunotherapy of HCC [16].