TLR7 and neoplasm: The design concept of immunostimulatory ADCs is to deliver immune agonists, such as Toll-like receptor 7/8 (TLR7/8) agonists or stimulator of interferon genes (STING) agonists, to the tumor microenvironment via antibodies, thus avoiding the toxicity issues that may arise from systemic administration of traditional immune agonists (121) (Figure 3).