Fig. 1.

An overview of using nanoparticles in cancer immunotherapy. The nanoparticles circulate in blood, and upon reaching the tumor site, they re-educate several tumor microenvironment components, including cancer-associated fibroblasts and tumor-associated macrophages, to finally activate the immune system. Moreover, nanoparticles can stimulate immunogenic cell death to enhance the maturation of dendritic cells for the activation of immune cells, such as T cells, to enhance cancer immunotherapy. The co-application of nanoparticles with immune checkpoint inhibitors, such as PD-L1 blockers, can augment the potential of cancer immunotherapy