The tumor microenvironment (TME) plays an important role in the development of
tumors. Immunoregulatory cells and
cytokines facilitate
cancer cells to avoid immune surveillance. Overexpression of
immune checkpoint molecules such as CTLA-4 and PD-1/PD-L1 inhibits immune function and enables
cancer cells to avoid clearance by the immune system. Thus, minimizing
tumor immunosuppression could be an important strategy for
cancer therapy. Currently, many immune checkpoint-targeted drugs, such as PD-1/
PD-L1 inhibitors, have been approved for marketing and have shown unique advantages in the clinical treatment of
cancers. The concept of "strengthening resistance to eliminate pathogenic factors" in
traditional Chinese medicine (TCM) is consistent with the
immunotherapy of
cancer. According to previous studies, the role of TCM in
tumor immunotherapy is mainly associated with the positive regulation of natural killer cells, CD8/CD4 T cells, dendritic cells, M2 macrophages,
interleukin-2,
tumor necrosis factor-[Formula: see text], and IFN-[Formula: see text], as well as with the negative regulation of Tregs, myeloid-derived suppressor cells, cancer-associated fibroblasts, PD-1/PD-L1,
transforming growth factor-[Formula: see text], and
tumor necrosis factor-[Formula: see text]. This paper summarizes the current research on the effect of TCM targeting the TME, and further introduces the research progress on studying the effects of TCM on immune checkpoints. Modern pharmacological studies have demonstrated that TCM can directly or indirectly affect the TME by inhibiting the overexpression of
immune checkpoint molecules and enhancing the efficacy of
tumor immunotherapy. TCM with immunomodulatory stimulation could be the key factor to achieve benefits from
immunotherapy for patients with non-inflammatory, or "cold",
tumors.