The combination of XB010 and an anti–PD-1 agent in a murine syngeneic colon cancer model enhanced tumor suppression compared with either compound administered alone, with mean tumor volumes reduced by ∼30-fold compared with controls, as well as %TGI of >95% and CRs in up to 90% of animals tested. This evidence concerns the gene PDCD1 and malignant colon neoplasm.