Cadonilimab, a tetravalent bispecific antibody targeting PD-1 and CTLA-4, is designed to retain the efficacy benefit of combination of PD-1 and CTLA-4 and improve on the safety profile of the combination therapy. The aim of this study is to evaluate the efficacy and safety of cadonilimab in combination with bevacizumab and standard chemotherapy as first Line therapy in unresectable pleural mesothelioma.