CTLA4 and hepatocellular carcinoma: Specifically, liver sinusoidal endothelial cells (LSECs), Kupffer cells (KCs), regulatory T cells (Tregs) [92], dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs) [93], natural killer cells (NKs) [94], immune checkpoints PD-1/PD-L1 [95], CTLA4 [96], lymphocyte activation gene 3 (LAG-3), glypican-3 (GPC-3), galectin 9 [97], immune-related cytokines [98] IL1, TNF-α, IFN-γ, IL-4, IL-5, IL-8 and IL10 are significant factors engaging in the maintenance of immune balance, which provides some hints for HCC immunotherapy.