CTLA4 and neoplasm: Tumor infiltrating lymphocytes (TILs) in the advanced HCC immune microenvironment tend to be dysfunctional with the enhanced expression of co-inhibitory molecules, including programmed death-1 (PD-1), cytotoxic T lymphocyte associated antigen 4 (CTLA-4), lymphocyte-activation gene 3 (LAG-3), and T cell immunoglobulin and mucin domain containing-3 (TIM-3) [43].