CD274 and neoplasm: 10 also revealed decreased colorectal tumor growth on PD‐1‐PD‐L1 blockade, in a macrophage‐dependent manner, through enhanced phagocytosis. Activated macrophages cause induction of iNOS (inducible NO synthase), NO (Nitric Oxide), or cytokine release [TNF‐α, IL‐6], causing decreased tumor growth and metastasis 28.