Nuclei from live-sorted CAR T cells (NGFR+) were isolated by 10 minute-centrifugation at 750g and 4°C in diH2O supplemented with 10 mM Tris-HCl pH 7.4, 10 mM NaCL, 3 mM MgCl2, 0.1% Tween-20, 0.1% IGEPAL, 0.01% Digitonin and 1% BSA. DNA was tagmented by Tn5 and then PCR-amplified with Nextera indexes for 12 cycles using NEB Next Ultra II Q5 polymerase. Libraries were double-size selected.