PD-1 blockade, a promising cancer therapy, only benefits a minority of patients. This study demonstrates that targeting IL-21 to tumor-reactive T cells using an IL-21-anti-PD-1 antibody fusion protein (PD-1Ab21) enhances memory T cell generation and antitumor effects in mice. PD-1Ab21 was superior to combined PD-1 blockade and IL-21 infusion, suggesting a potential strategy to improve immune checkpoint blockade therapy.
