CD8A and obesity due to melanocortin 4 receptor deficiency: firstly identified the effect of obesity on MDSC-mediated immunotherapy resistance in a BC mouse tumor model and found that obesity could lead to the accumulation of FasL+ granulocytic MDSCs, thus promoting apoptosis of tumor-Infiltrating CD8 T cells and immunotherapy (adenovirus encoding TRAIL + CpG) resistance in BC (145).