CD8A and neoplasm: While PI3Kδ isoform-specific PI3K inhibitor selectively depletes Tregs, the number of CD8+ T cells is increased through PI3Kδ specific inactivation in Tregs, resulting in the prevention of tumor progression and metastasis.125 126 In fact, since Tregs and effector T cells such as CD8+ T cells have differences in PI3Kδ dependency, the inhibitor could specifically target Tregs.