This dual action significantly inhibits GC cell proliferation, migration, and invasion while promoting DC maturation (evidenced by elevated CD80/CD86 expression) and CD8+ T‐cell activation. In vivo, iRGD modification boosts tumor accumulation of NPs, and NP‐mediated PDT synergized with SOX9 silencing to suppress tumor growth in GC xenografts. Here, CD86 is linked to neoplasm.