The lipid‐polymer nanoparticles can reach glioblastoma within 2 h post intravenous administration, and hypoxia in tumor cells triggers charge‐elimination and degradation of the cationic polymer for burst release of Cas9 and sgRNA, accompanied by instant Cas9 RNP assembly, yielding ≈50% STAT3 knockout. The gene discussed is STAT3; the disease is glioblastoma.