TLR9 and neoplasm: As EVs are endocytosed by DCs via endosomes where TLR3, TLR7, TLR8, and TLR9 are present23–26,36,37, we hypothesize that the display of sufficient TLR3/7/8/9 agonists on EVs can timely stimulate TLRs on the surface of intracellular endosomes, resulting in the improved activation of DCs during the endocytosis of tumor EVs (Fig. 1b).