Our findings suggest that pseudogene HLA-DPB2 can upregulate HLA-DPB1 through sponging has-miR-370-3p, thus exerting its antitumor effect by recruiting tumor-infiltrating immune cells into the breast tumor microenvironment, and that targeting the HLA-DPB2/HLA-DPB1 axis with ICIs may optimize the current immunotherapy for BC. This evidence concerns the gene HLA-DPB2 and breast cancer.