DPP4 and chronic myelogenous leukemia, BCR-ABL1 positive: Preliminary data in 47 newly diagnosed CML patients showed that the co-expression of PD-L1 on their CD26+LSCs is variable: 22/47 (47%) patients scored negative while 25/47 (53%) scored positive, albeit with a quite variable percentage of expression (median 28.5% of CD26+ cells, range 12%–82.8%) (Pacelli et al., 2022).