CD38 and neoplasm: In this study, we characterized the MDSCs of ESCC with CD38 and CD33, verified that AZD4547 could inhibit the recruitment of MDSCs through the CXCL8–CXCR2 axis in tumor tissues of hu-HSC-NOG-EXL mice, and verified the tumor suppressive effect of AZD4547 combined immunotherapy in ESCC.