To complement these findings and further explore the extent to which the CXCR3/CXCL9/10/11 axis might contribute to the increased homing and efficacy of PTPN2‐deficient CAR T cells, we sought to repress the Cxcl9/10 expression in HER‐2‐E0771 mammary tumours and assess the impact on the homing and function of PTPN2‐deficient CAR T cells (Fig 7D–H). This evidence concerns the gene CXCL9 and breast cancer.