TLR9 and hepatitis B virus infection: In the current treatment of chronic hepatitis B based on thymosin and entecavir, emphasis is placed on whether TLR9 affects the body’s immunity, whether HBV regulates TLR9 expression, whether TLR9 is related to the therapeutic effect, and the mechanism of action of TLR9 in patients with hepatitis B, all of which will provide an important theoretical basis for determining the pathogenesis of chronic hepatitis B and the clinical antiviral mechanism.