PDCD1 and B-cell chronic lymphocytic leukemia: Within the CD4 compartment, CD4 TEM GZMK cells and all CD4 TREG clusters (CD4 TREG-CM1, CD4 TREG-CM2, CD4 TREG PD1, and CD4 TREG CD39) were also enriched in CLL LNs, in addition to proliferating TPR cells and DN TEM HELIOS cells (Fig. 3D).