Immunotherapy has attracted tremendous attention due to the remarkable clinical successes for treating a broad spectrum of tumors.One challenge for cancer immunotherapy is the inability to control localization and sustain concentrations of therapeutics at tumor sites.Local drug delivery systems (LDDSs) like the biomaterial scaffold-based drug delivery systems have emerged as a promising approach for delivering immunotherapeutic agents facilely and intensively in situ with reduced systemic toxicity.In this review,recent advances in biomaterial scaffold-based LDDSs for the administration of immunotherapeutic agents including vaccines,immunomodulators,and immune cells are summarized,Moreover,codelivery systems are also evaluated for local immunotherapy-involving combination anti-tumor therapy,including chemotherapy-immunotherapy,photothermal-immunotherapy,and other combination therapies.Finally,the current challenges and future perspectives on the development of next-generation LDDSs for cancer immunotherapy are discussed.