PDCD1 and B-cell chronic lymphocytic leukemia: PB and BM samples were enriched in SLEC T cells, such as CD8 TEM TBET, CD4 TEM TBET, and DN TEMRA TBET, while CLL LNs contained higher frequencies of exhausted T cells (CD8 TEX CD39 and CD8 TEX CD38), CD4 TEM GZMK cells, CD4 TFH cells, several CD4 TREG subsets (CD4 TREG-CM1, CD4 TREG PD1, and CD4 TREG CD39), as well as proliferating cells (TPR) (Fig. 3C).