The cellular orchestra of CAR T success.

In this issue of Cancer Cell, Rade et al. report a longitudinal single-cell atlas of multiple myeloma patients receiving BCMA-directed chimeric antigen receptor (CAR) T cell therapy (ide-cel or cilta-cel) and identifiy features linked to long-term responses, including CD4+ T cell-driven cytotoxicity, memory-biased T cell states, reduced exhaustion, and microenvironment effects.