Figure 1.

The interaction between HNSCC tumor cells and the immune system. 1) The immune system of HNSCC tumor tissues includes immune cells, immune checkpoints, and immune microenvironment; 2). Immune checkpoints such as PD-1/PD-L1 and CTLA-4/B7 can inhibit the proliferation and infiltration of cytotoxic T lymphocytes; 3) MDSC, Treg cells, NK cells and cytotoxic T lymphocytes are involved in the elimination of tumor cells; 4) Tumor cells and immune cells can also interact with each other through cytokines.