In an observational study of 90 patients receiving chimeric antigen receptor T-cell (CAR-T) therapy, the plasma levels of interleukin-6 (IL-6) and IL-15 in patients with new-onset fibrillation events during treatment were significantly higher than those in the group without AF, which may be associated with the development of AF (13). Here, IL6 is linked to atrial fibrillation.