CD274 and breast cancer: using a mouse model of breast cancer also revealed that tumor‐infiltrating B cells (TIBs) highly express PD‐L1.[79] These TIBs promote T cell depletion, suppress NK cell proliferation, and inhibit T cell production of cytokines such as IFN‐γ and tumor necrosis factor‐α (TNF‐α), thereby contributing to tumor growth.[79] Similar findings were observed in other studies investigating on breast cancer and pancreatic cancer.[51, 80]