Tumor growth inhibition induced by anti-muPD-1-muGITR-L was different from the effect of single agents (anti-muPD-1 and isotype-muGITR-L, where isotype variable domain is an anti-huCMV, clone MSL109) and a 1:1 combination in anti-PD-1-resistant syngeneic tumor models including CT26, EMT6 and JC (Fig. 6a–c). Here, PDCD1 is linked to neoplasm.