While numerous forms of immunotherapy have been developed over the past century, including rather untargeted approaches (e.g., the systemic delivery of immunostimulatory cytokines such as IL2) as well as highly specific interventions (e.g., therapeutic vaccination based on one or several tumor-specific antigens)199, only a few of these approaches are approved by regulatory agencies and routinely employed in cancer patients24. The gene discussed is IL2; the disease is cancer.