Given the recent approval of PD-1/PD-L1 immune checkpoint blockade (ICB) for various cancer types 14, we examined the efficacy of anti-mouse PD-1 mAb in this model to determine its ability to enhance T cell-mediated immunity, an effect clinically reflected by higher densities of PD-1+ tumor-infiltrating lymphocytes and PD-L1+ tumors associated with improved patient outcomes 15, 16. This evidence concerns the gene CD274 and cancer.