It was subsequently put forth that the recognition of CT26 tumor cells by CTLs in the model may have been impeded by programmed cell death protein 1 (PD-1)–programmed-death ligand 1 (PD-L1) interaction, thus, preventing CTL delivery of mGzmA into target CT26 cells and induction of CT26 cell pyroptosis. Here, PDCD1 is linked to neoplasm.