Fig. 1.

Dynamic changes in cellular components in the HCC TME. a According to cell functions in the TME, the TME can be refined into the tumor immune microenvironment (TIME). Due to the specific features of the liver, the role of tumor-associated macrophages (TAMs) in the liver TIME is prominent. As shown, during the development of HCC, the expression of immunosuppressive checkpoint molecules (Tim-3, PD-1, and TLR) on the surface of TAMs affects the accumulation and antigen presentation of cell performing immune surveillance. b Blocking immune checkpoint molecule expression and reversing the phenotype of macrophages are two main approaches to regulate the tumor immune microenvironment discussed in this review. As shown above, increased infiltration of T cells and M2 macrophages can effectively inhibit the growth, metastasis, and invasion of tumor cells at the cellular level, which in turn achieves superior immunotherapeutic efficacy