CD33 and nasopharyngeal carcinoma: The levels of immunosuppressive myeloid cells, including immature CD11b+CD14+ monocytes, CD33+ myeloid cells, CD33+CD11+ myeloid cells, total MDSCs (CD33+CD11+HLA‐DR−/low), CD14+ monocytic MDSCs, and CD15+ granulocytic MDSCs (Figure S2), was significantly higher in NPC patients compared to healthy donors.