Importantly, this effect was not specific to the progressing B16‐cOVA tumor, as OT‐I cells responding within the context of TFLN to established D5.1G4‐cOVA (both 7‐ and 14‐day‐old tumors) failed to fully differentiate into IFNγ‐secreting effectors as well. The gene discussed is IFNG; the disease is neoplasm.