This clinical trial, sponsored by Peking University, aims to evaluate the effectiveness and safety of a combination therapy involving decitabine, TQB2450 (a PD-L1 monoclonal antibody), and anlotinib in patients with digestive system tumors that have shown resistance to PD-1 inhibitors. The market for cancer therapies, particularly those targeting immune resistance mechanisms, is rapidly expanding, with significant competition from existing PD-1/PD-L1 inhibitors and emerging combination therapies. Successful outcomes could position the sponsor favorably within this competitive landscape, particularly if they demonstrate improved efficacy in a patient population with limited treatment options. Diligence should focus on the trial's recruitment status and the regulatory pathway for TQB2450, as well as potential partnerships for commercialization.