This is a Phase Ib/II study to assess the safety, tolerability and preliminary efficacy of AK119 combined with AK112 in patients with advanced solid tumors.

Inclusion Criteria:

1. Voluntarily written informed consent and agree to comply with all protocol-specified procedures and follow-up evaluations
2. Age ≥ 18 years and ≤ 75 years
3. Histologically or cytologically-confirmed diagnosis of advanced/unresectable solid tumor that have been progressed or intolerant to at least one standard treatment regimen in the advanced or metastatic setting, if such a therapy exists
4. Measurable lesion based on RECIST v1.1
5. ECOG status of 0 or 1
6. Life expectancy ≥ 3 months
7. Adequate organ function
8. Women of childbearing potential and men with female partners of childbearing potential must agree to use effective contraception during treatment and for at least 120 days following the last dose of study treatment

Exclusion Criteria:

1. Known other active malignancy within 3 years prior to the first dose of investigational product, with the exception of early stage cancers that have treated with curative intent
2. Currently participating in another study unless it is an observational, non-interventional clinical study or a follow-up period of an interventional study
3. Received systemic antineoplastic therapy ( e.g. chemotherapy, radiotherapy, immunotherapy) within 4 weeks prior to the first dose of investigational product; received small-molecule anticancer agents within 2 weeks prior to the first dose of investigational product
4. In addition to anti-PD-(L)1 monoclonal antibody, prior exposure to other immune checkpoint inhibitors or any other treatment directed to tumor immune mechanism
5. Prior therapy targeting CD73 or CD39 or the adenosine signalling pathway
6. Treatment with non-steroidal anti-inflammatory drugs, anti-platelet agents or anticoagulants within 7 days prior to the first dose of investigational product
7. Current dependency on systemic therapy with glucocorticoids (>10 mg/day prednisone or equivalent) or other immunosuppressive agents within 14 days prior to the first dose of investigational product
8. Presence of spinal cord compression or active brain metastases
9. Uncontrolled pleural effusion, pericardial effusion or ascites requiring repeated drainage
10. History or presence of a serious hemorrhage or known bleeding tendency within 3 months
11. Active autoimmune disease that has required systemic treatment in past 2 years
12. Clinically significant cardiovascular disease
13. History of interstitial lung disease or noninfectious pneumonitis
14. Received systemic anti-infective therapy (excluding antiviral therapy for hepatitis B or C) within 14 days prior to the first dose of investigational product
15. Major surgical procedure or serious trauma within 28 days prior to the first dose of investigational product
16. History of immunodeficiency, human immunodeficiency virus infection (HIV)
17. Active tuberculosis or syphilis infection
18. History of organ transplantation or allogeneic haematopoietic stem cell transplantation
19. Toxicities of prior anticancer therapy have not resolved to ≤ Grade 1 (NCI-CTCAE version 5.0)
20. Any other conditions that, in the opinion of the Investigator, would interfere with evaluation of the investigational product or interpretation of subject safety or study results