TREM2 and diffuse large B-cell lymphoma: Given that (1) M-MDSCs possess immunosuppressive ability and impair immunotherapeutic effectiveness in DLBCL patients, (2) a higher percentage of circulating M-MDSCs in PB is associated with worse survival in DLBCL patients, (3) both M-MDSCs and M2 macrophages belong to the monocytic lineage, and (4) TREM2 are well known M2-polarization markers and exert an anti-inflammatory nature, we hypothesize that TREM2 could be expressed on M-MDSCs to augment their immunosuppressive ability, leading to a poor outcome in DLBCL patients.