A meta-analysis evaluating the efficacy, safety, and potential mechanisms of TCM as an adjuvant therapy in cancer immunotherapy indicated that TCM influenced PD-1/PD-L1 inhibitors through tumor microenvironment modulation, gut microbiota regulation, inhibition of PD-1 or PD-L1 expression, and cytokine signaling regulation (107). This evidence concerns the gene PDCD1 and neoplasm.