While a commercially available canine PD-1 antibody remains in-development, several translationally impactful studies have emerged over the past 5 years describing in vitro biologic activity and in vivo therapeutic potential of anti-PD-1, anti-PD-L1, or other checkpoint blocking molecule strategies alone or in combination in cancer-bearing dogs (47, 120, 131, 132, 198, 199). This evidence concerns the gene CD274 and cancer.