Two products of this enzymatic reaction, urea and nitric oxide (NO), induce T cell depletion and inhibit T cell function.18, 31, 36, 37 Moreover, mMDSCs attract Tregs through C-C motif chemokine ligand 2 (CCL4) and CCL5 production, secrete IL-10,38 and upregulate PD-L1 on their cell surface, which inhibits tumor-specific T cell cytotoxicity.39 Here, CD274 is linked to neoplasm.