PCSK9 and hyperlipidemia: Herein, a novel copolymer for delivery of Cas9‐mRNA/ single‐guide RNA (Cas9‐mRNA/sgRNA) in vitro and vivo, using carboxylesterase‐responsive cationic triadic copolymeric nanoparticles targeted proprotein convertase subtilisin/kexin type 9 (PCSK9) for hyperlipidemia amelioration is reported.