CD226 and B-cell chronic lymphocytic leukemia: Considering the variability of T cell subpopulations in CLL versus HCs (Fig. 2E), we measured the frequency of CD226+ cells among different T cell subsets, including naïve (CD45RA+CCR7+), central memory (CM; CD45RA‐CCR7+), effector memory (EM; CD45RA−CCR7−), and effector cells (EFF; CD45RA+CCR7−) (Fig. 2F).