TLR9 and neoplasm: In terms of TLR ligand-targeted modulation of NK cells, TLR8 agonists (e.g., R848) and TLR9 agonists (e.g., ODN2006) can respectively regulate immunomodulatory and cytotoxic NK cells, increase the expression of activation receptors such as NKG2D and NKp44, and synergistically enhance anti-tumor activity (125).