Activation-dependent biological activity of GzB-IL18 in αβ and γδ CAR T cells is indicated by induction of nuclear factor κB (NF-κB)/AP1 activity in IL18-selective reporter cells, accompanied by enhanced tumor cytolytic capacity, IFN-γ release, T cell proliferation, and tumor control in both immunodeficient and immune-competent mice. The gene discussed is IL18; the disease is neoplasm.