In contrast, CLL‐derived CAR T cells retained a CD4‐dominant profile suggesting limited CD8+ expansion, as also described by Stock et al.36In addition, the diminished cytotoxicity and elevated expression of exhaustion markers, particularly in scaffold core regions, extend prior reports of T‐cell dysfunction in CLL,12, 37, 38, 39, 40, 41 and suggest that both intrinsic and spatially organized extrinsic factors of the TME contribute to therapeutic failure. Here, CD8A is linked to B-cell chronic lymphocytic leukemia.