Wu et al. found that the only inhibitory receptor in the Fcγ receptor family, FcγRIIB, was expressed in tumor-infiltrating MDSCs by constructing a mouse model of Fc γ receptor IIB receptor deficiency in the Immunoglobulin (Ig) Fc region, and using adoptive cell transfer, mRNA sequencing, and flow cytometry analysis to discover that the only inhibitory receptor in the Fcγ receptor family was responsible for upregulating the presence of tumor-infiltrating MDSCs. Here, FCGR2B is linked to neoplasm.