CD8A and breast cancer: Using a mouse model of breast cancer, Demaria et al. [76] found that the combination of local RT and CTLA-4 blockade significantly inhibited the growth and metastasis of primary tumors and produced better response outcomes in patients with spontaneous metastasis and low-immunogenicity breast cancer compared to treatment alone, and the intrinsic mechanism may be that combination therapy induces more CD8+T cells with enhanced activity, which is propitious to CTLA-4 antibody-mediated tumor immunotherapy treatment.