CD8A and B-cell chronic lymphocytic leukemia: Notably, CLL‐derived CD8+ CAR T cells exhibited significantly higher PD‐1 expression than their ALL‐derived counterparts after transduction and expansion (CLL: 25.8% ± 5.2 vs. ALL: 12.5% ± 3.6, P < 0.05, Figure 1G, middle panel).