In this study, four MDSC subsets were analyzed in the PBMCs of advanced melanoma patients, at baseline and 12 weeks after Ipilimumab: CD14+IL-4Rα+ M-MDSCs, CD14+HLA-DRlow/− M-MDSCs, Lin−HLA-DR−CD33+CD11b+ eMDSCs, and CD15+IL4-Rα+ PMN-MDSCs. Here, IL4R is linked to melanoma.