PDCD1 and neoplasm: APCs with PD-L1 expression play a dominant role in the regulation of T-cell immunity and the response to cancer immunotherapy in the context of cancer.278,279 On the other hand, PD-1 on macrophages inhibits the phagocytosis of tumor cells, and PD-1-positive TAMs are associated with a reduction in 5-year overall survival in the context of cancer.9,235 Therefore, the PD-1-PD-L1 axis interacts with both the innate and adaptive immune systems in the TME.