STING1 and neoplasm: c-di-GMP (CDG), a STING pathway activator, was loaded onto mesoporous silica nanoparticles by Chen et al. (Chen et al., 2020) and found that it could protect the encapsulated CDG from rapid digestion and degradation by enzymes in serum, and the passive targeting of tumor sites was achieved through the EPR effect of MSN, which effectively reduced the systemic toxic side effects of CDG alone.