T-cells represent valuable tools for treatment of cancers, infectious or inherited diseases but they are mainly short-lived in vivo. T-cell therapies would strongly benefit from gene transfer into long-lived persisting naive T cells or T-cell progenitors. During the ASGCT 2019 congress (Washington 2019), INSERM partner presented latest published data on the generation of efficient gene-corrected T-cell progenitors from SCID patients.