CD274 and neoplasm: Although recent study showed that ART decreases MDSC frequencies in 4T1-bearing mice [47] and improves the efficiency of anti-PD-L1 blockade in T cell lymphoma-bearing mice [39, 40], how ART influences MDSC accumulation, function, and molecular pathways in melanoma or liver tumors and further enhances PD-L1 blockade-mediated tumor immunotherapy remains unknown.