Peritoneal metastasis carcinoma (PMC), as an extremely aggressive malignant tumor with high metastatic potential, typically exhibits an average clinical survival period of less than 9 months. Unfortunately, the existing treatment modalities, including surgical resection and localized hyperthermic intraperitoneal chemotherapy (HIPEC), often only provide temporary suppression of tumor growth, offering limited improvement in overall patient survival. We previously reported a biopolymer immune implant which could sustainably release the loaded chemo-immunotherapeutic agents for effectively stimulating systemic antitumor immune responses. Herein, we optimized the terminal groups (hydrazide, hydroxylamine, and amine) of the 4-arm PEG to achieve more stable and longer drug release especially in large animals. The selected implant based on oxime bonds demonstrated superior performance in terms of mechanical strength, prolonged degradation time and sustained drug release in preclinical evaluations, which is crucial for the immune activation of immunotherapeutic drugs. Safety evaluations in rats and rabbits demonstrated excellent biocompatibility. The implants, loaded with a combination of chemotherapy oxaliplatin (OxP) and immunostimulant resiquimod (R848), showed significant therapeutic efficacy in a gastric cancer PMC model, achieving a tumor inhibition rate exceeding 96%. Furthermore, the immunological responses post-treatment revealed increased infiltration of CD4+ and CD8+ T cells, activation of dendritic cells within the tumor. The results support the clinical translation potential of these implants for PMC therapy, offering a potential breakthrough in the challenging landscape of cancer treatment. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)9(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) (sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic) (sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)-(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)PEG(sic)(sic)(sic)(sic)(sic)((sic)(sic),(sic)(sic)(sic) (sic)(sic)(sic)), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) (sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)96%. (sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).