PDCD1 and neoplasm: Blocking the macrophage colony‐stimulating growth factor‐1 receptor (csf‐1r), reducing the frequency of TAMs, can increase the production of IFN, and improve the response of tumor cells to drugs. Csf‐1r blocker combined with PD‐1 or CTLA‐4 antibody, and then combined with gemcitabine, the treatment effect is better