CD274 and neoplasm: Blocking PD‐1‐PD‐L1 axis by anti‐PD‐1 antibody or a PD‐L1 blocker increased tumor‐engulfment and reduced tumor progression in immunocompromised mice lacking the adaptive immune system but retaining functional macrophages, which suggests that PD‐1‐PD‐L1 interactions can inhibit tumor‐phagocytosis in a macrophage‐dependent manner.