CD4 and hepatocellular carcinoma: In patients with hepatocellular carcinoma (HCC) with underlying chronic cirrhosis, persistent inflammation leads to PD-1/PD-L1 overexpression and upregulation of other immune checkpoint molecules (CTLA-4, LAG3, and TIM3), resulting in cytotoxic CD8+ T-cell depletion and CD4+ Foxp3 Treg cell recruitment.