Occurrence of immune tolerance in HCC patients is due to enrichment of regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and alteration of immune checkpoint molecules, such as T-lymphocyte-associated protein-4 (CTLA-4) and programmed cell death protein-1 (PD-1) [11,17]. Here, CTLA4 is linked to hepatocellular carcinoma.