PTPN2 and neoplasm: In those mice in which tumours had previously been cleared, splenic PTPN2‐deficient CAR T cells had a central memory phenotype (CD44hiCD62Lhi) rather than the mixed central and effector/memory (CD44hiCD62Llo) phenotypes otherwise present on day 10 post‐adoptive transfer (Fig 5F and G), consistent with PTPN2 deficiency promoting CAR T‐cell memory.