Delta-like ligand 3 (DLL3), overexpressed in >80% of SCLC, enables T-cell–redirecting therapy: the bispecific T-cell engager (BiTE®) tarlatamab improved OS to 13.6 vs 8.3 months over standard second-line chemotherapy, with manageable cytokine release syndrome and occasional ICANS. Here, DLL3 is linked to small cell lung carcinoma.