Moreover, considering the heterogeneity of HER2 expression and the immunosuppressive tumour microenvironment, genetic research should focus on designing CAR T cells with enhanced anti-tumour activity and ability to target multiple antigens, and on reversing the immunosuppressive tumour microenvironment, for example by associating PD-L1 or PD-1 inhibitors [79]. Here, ERBB2 is linked to neoplasm.