FOXO1 overexpression significantly increased the proportion of CD8+ CAR T cells in the tumours of treated mice at day 12 post-treatment (Fig. 5e) and in both tumours and spleens, wild-type FOXO1-overexpressing CD8+ CAR T cells exhibited a less-differentiated phenotype (Fig. 5f,g). Here, CD8A is linked to neoplasm.