TNF and neoplasm: In vivo, HVEM-CAR T cells showed superior tumor control, prolonged survival, and increased intratumoral abundance compared to 4-1BB-CAR or AVEE-mutated HVEM-CAR T cells.<h4>Conclusions</h4>HVEM enhances CAR T cell efficacy against solid tumors by robustly activating TNF signaling through TRAF recruitment, particularly via the AVEE motif.