COVID-19 outcomes and vaccine efficacy tend to be worse in patients undergoing hematopoietic stem-cell transplantation due to the immunosuppressants patients are required to take. Lena Peter, Berlin Institute of Health Center for Regenerative Therapies, Berlin, Germany, discusses the development of adoptive T-cell products to treat immunosuppressed patients with COVID-19. Donor-derived T-cells were engineered to be tacrolimus-resistant via FKBP12 gene knockout and single cell RNA sequencing determined successful gene silencing. The modified T-cells were found provide patients protection against COVID-19 as well as its variants, and remaining sensitivity to cyclosporine A ensures additional safety in patients. This interview took place at the International Conference on Lymphocyte Engineering (ICLE) 2022.