IFNA1 and chronic myelogenous leukemia, BCR-ABL1 positive: As shown in Fig. 3, CD4+ T cells expressed higher levels of PD1 in both CML treatment groups, with a statistically significant difference being detected when comparing patients on TKIs plus IFN-α and controls (1.65% versus 0.8%; p = 0.023; Fig. 3a).