Two immune checkpoint inhibitor monotherapies for HCC treatment have been approved by the FDA, nivolumab and pembrolizumab, which implement an IgG4 monoclonal antibody (mAb) that binds to PD-1, blocking interaction with its ligands, PD-L1 and PD-L2 [18,19]. Here, PDCD1 is linked to hepatocellular carcinoma.