Application of nanoscale metal–organic frameworks in tumor immunotherapy

Immunotherapy has attracted wide attention because it can not only kill tumor cells but also effectively prevent tumor recurrence. However, due to the poor efficacy of the monotherapy in tumor immunotherapy, combination therapies are needed to enhance their efficacy, such as chemodynamic therapy/immunotherapy, photodynamic therapy/immunotherapy, sonodynamic therapy/immunotherapy and so on. Nanoscale metal–organic frameworks (nMOFs) are widely used for drug delivery because of their rich and variable composition, high drug loading capacity and good biodegradability. Compared with other conventional drug delivery systems (DDSs), nMOFs play more advantageous role in inducing immune cell death of tumor cells and combination therapies. This article focuses on the application of nMOFs in tumor immunotherapy in terms of their use as gatekeepers, supplementary agents and drug carriers, respectively, with the aim of providing some ideas and references for the design of smart nanoscale DDS for tumor immunotherapy.