Initiated by Motta et al. [40], and followed by Nunes et al. [11] and Riches et al. [9], higher expression of PD-1 [9, 11, 49, 71, 74, 77, 78], CD160 [9], CD244 [9], T-cell immunoglobulin mucin 3 (TIM-3) [78], killer cell lectin-like receptor G1 (KLRG1) [75] and CTLA-4 [7, 40] was reported on CD8+ T-cells in the blood of CLL patients. Here, KLRG1 is linked to B-cell chronic lymphocytic leukemia.