A review and commentary.Understanding immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for optimizing treatment of COVID-19.In this issue of Blood, M.D. Keller and colleagues (ibid., 2905-2917) generated SARS-CoV-2-specific cytotoxic T lymphocytes (CTLs) from the blood of individuals recovered from infection.The rapid application of this good manufacturing practice (GMP)-compliant system raises the possibility that banked third-party SARS-CoV-2 CTLs could be used for treatment.