MDSCs are the most abundant precursor cells in the bone marrow (BM), migrating to peripheral tissues and the tumor microenvironment (TME), where they express elevated levels of arginase 1 (ARG1), inducible nitric oxide synthase (iNOS/NOS2), PD‐L1, and reactive oxygen species (ROS), among other immunosuppressive molecules [4, 5]. The gene discussed is NOS2; the disease is neoplasm.