CTLA4 and hepatocellular carcinoma: Agents such as ipilimumab (CTLA-4 inhibitor), nivolumab, pembrolizumab (PD-1 blockers), and durvalumab (PD-L1 blocker) are approved by the Food and Drug Administration (FDA) to treat many tumor types, including melanoma, renal cell carcinoma (RCC), urothelial cancers, non-small cell lung cancer (NSCLC), small cell lung cancer, Hodgkin’s lymphoma (HL), hepatocellular carcinoma (HCC), colorectal cancer, and squamous cell carcinoma of head and neck, among many others [1-3].