Phase Ib/II open label, multicenter study to evaluate the efficacy and safety of AK104 (anti-PD-1 and CTLA-4 bispecific antibody) and AK117#AntiCD47 Antibody# combined with or without chemotherapy in advanced malignant tumors

Inclusion Criteria:

1. 18 to 75 years old.
2. Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
3. Have a life expectancy of at least 3 months.
4. Phase Ib: Histologically or cytologically confirmed advanced solid tumor.
5. Phase II: Has histologically confirmed diagnosis of unresectable locally advanced,recurrent or metastatic gastric or GEJ adenocarcinoma or Esophageal squamous cell carcinoma.
6. Have at least one measurable lesion based on Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 assessed by investigator.
7. Has adequate organ function.

Exclusion Criteria:

1. Undergone major surgery within 30 days prior to the first dose of study treatment.
2. Active central nervous system (CNS) metastases.
3. History of active autoimmune disease that has required systemic treatment in the past 2 years (i.e.,corticosteroids or immunosuppressive drugs).
4. Active Hepatitis B or Hepatitis C.
5. Received previous immunotherapy, including immune checkpoint inhibitors, immune checkpoint agonists, immune cell therapy and other treatments targeting the mechanism of tumor immunity.
6. History of severe bleeding tendency or coagulation disorder.