Antigen‐specific immune recognition and eradication of infected cells require CTLs, which ensure a swifter response upon antigen reexposure.[17] To explore whether mOVA@NPs could reprogram tumor cells to prime OVA‐specific CTLs for cellular killing, we used OT‐1 mice to investigate the killing efficiency of CD8+ T cells against OVA peptides on the tumor cell surface. Here, CD8A is linked to neoplasm.