LAG3 and hepatocellular carcinoma: The expression of immune checkpoint molecules, such as programmed death-1 (PD-1), cytotoxic T-lymphocyte antigen 4 (CTLA-4), lymphocyte activating gene 3 protein (LAG-3), and mucin domain molecule 3 (TIM-3) on tumor and immune cells as well as the high levels of immunosuppressive cytokines induce T cell inhibition and represent a major mechanism of HCC immune escape.