PDCD1 and neoplasm: Durvalumab is an IgG1 κ monoclonal antibody, which acts as a PD-L1 blocker, can bind to PD-L1 on tumor cells, and block its interaction with PD-1 of T cells and antigen-presenting cells, thereby relieving PD-1/PD-L1-mediated immunouppression, promoting T cell proliferation, and strengthening the immune killing effect on tumors.