Immunostimulant therapy using agonistic cytokines or activating antibodies has been associated with off-target side effects, failure to preferentially activate cytotoxic lymphocytes (CTLs) over regulatory T cells (Treg), and the development of T-cell exhaustion. With the aim of overcoming these issues, researchers from Recourse Biologics Inc. designed a potentially first-in-class immunostimulatory fusion protein.