In murine models, durable tumor regressions have been observed with a single-agent OX40 agonist in combination with programmed cell death protein 1 (PD-1) blockade10,11 and antitumor activity was shown with approaches using mRNA encoding OX40L.12 Thus, induction of OX40L expression is a potential strategy for enhancing antitumor immunity through stimulation of tumor-specific T-cell activation, resulting in local and systemic antitumor responses. The gene discussed is TNFSF4; the disease is neoplasm.