In summary, our data suggest that T cell-tropic AAV vectors can support unprecedented high levels of HDR-mediated genome editing including both gene correction (small nucleotide changes) and targeted gene addition strategies in both primary CD8+ and CD4+ T cells, which could have broad applications in the development of improved T cell immunotherapies for a broad range of indications, including cancer, chronic infection and autoimmunity. This evidence concerns the gene CD4 and cancer.