In a phase I clinical trial using RNA lipoplexes, over 75% of the trial subjects thus far have shown immune responses against at least one tumor‐associated antigen, as well as activation of antigen‐specific CD8+ T cells.[161] Combination with programmed cell death protein 1 (PD‐1) checkpoint blockade further improved treatment efficacy, resulting in a 35% tumor regression rate. Here, PDCD1 is linked to neoplasm.