ANTI-4-1BB-ANTI-PD-L1 BISPECIFIC ANTIBODY, AND PHARMACEUTICAL COMPOSITION AND USE THEREOF

The present invention relates to an anti-4-1BB-anti-PD-L1 bispecific antibody, and a pharmaceutical composition and the use thereof. Specifically, the present invention relates to a bispecific antibody, which comprises a first protein functional region targeting 4-1BB and a second protein functional region targeting PD-L1 or PD-1, wherein the first protein functional region is a single-domain antibody against 4-1BB; and the second protein functional region is an anti-PD-L1 antibody, anti-PD-1 antibody, anti-CTLA-4 antibody or anti-HER-2 antibody, or an antigen-binding fragment thereof. The bispecific antibody has the function of blocking the binding of PD-L1 to a receptor PD-1, and binds to 4-1BB on an immune cell, such that the immune cell activity in a tumor microenvironment is activated and the effect of inhibiting tumor occurrence and development is improved more effectively.