Rusak et al. concluded that treatment-naive patients with CLL with the number of CD4+/PD1+ T cells exceeding 15.79% at baseline showed a significantly shortened time to the first treatment compared with CLL patients with lower CD4+/PD1+ T cell numbers (6 months vs 18.5 months, respectively, P = 0.006) (22). Here, CD4 is linked to B-cell chronic lymphocytic leukemia.