Traditional treatment methods, including chemotherapy and radiotherapy, have limited therapeutic effects, and the side effects may cause unexpected damage to patient's normal tissues, which may accelerate the deterioration of the patient's condition or even threaten life . Therefore, new therapeutic methods need to be developed to improve the tumor therapeutic effects. Immune checkpoint blockade (ICB) immunotherapy has achieved remarkable tumor inhibitory effects by activating endogenous anti-tumor T cells to kill cancer cells. Among multiple checkpoint inhibitors, programmed death 1 (PD-1) and its predominant ligand, programmed death ligand 1 (PD-L1) are key immune checkpoint molecules, which are closely related to immune resistance . Blocking the PD-1/PD-L1 pathway is expected to rejuvenate exhausted CD8 + T cells to boost anti-tumor immune responses . Currently, most checkpoint inhibitors targeting the PD-1/PD-L1 are monoclonal antibodies .