1. Squamous cell carcinoma, undifferentiated or other non-adenocarcinoma histologic type of gastric cancer or gastro-esophageal tumor;
2. Subjects with known contraindications to cadonilimab, CapeOX (see package inserts for cadonilimab, oxaliplatin, and capecitabine);
3. Known history of severe intolerance to cadonilimab, oxaliplatin, or capecitabine (i.e., grade 4 toxicity of one of the agents; grade 3-4 toxicity of other concomitant agents is not excluded);
4. Known history of hypersensitivity or hypersensitivity to cadonilimab, oxaliplatin, other platinum compounds, or fluorouracil;
5. Known brain or meningeal metastases:
6. Radiotherapy or any anti-tumor therapy (chemotherapy, targeted therapy, immunotherapy, radio-frequency ablation, traditional Chinese medicine with anti-tumor indications, immunomodulators or tumor embolization, etc.) within 4 weeks prior to the first dose of study treatment;
7. Prior exposure to any anti-PD-1, anti-PD-L1, anti-CTLA-4 antibodies, or any other antibody or drug therapy against T cell co-stimulation or checkpoint pathways;
8. Patients have had other malignancies within the past 5 years or at the same time (except for cured basal cell carcinoma of the skin and carcinoma in situ of the cervix);
9. There are obvious clinical bleeding symptoms or obvious bleeding tendency, hemoptysis, etc. within 3 months before treatment. or venous/venous thrombotic event treatment within the preceding 6 months, such as cerebrovascular accident (including transient ischemic attack, intracerebral hemorrhage, cerebral infarction), deep vein thrombosis, and pulmonary embolism; or requiring long-term anticoagulation with warfarin or heparin, or requiring long-term antiplatelet therapy (aspirin≥ 300 mg/day or clopidogrel ≥75 mg/day);
13. Any other disease, clinically significant metabolic abnormality, physical examination abnormality, or laboratory abnormality that, in the judgment of the investigator, has reason to suspect that the patient has a certain disease or state that is not suitable for the use of the study drug;
14. Any condition that, in the opinion of the investigator, may put subjects treated with study drug at risk, interfere with the study drug, subject safety assessment, or interpretation of results.