This is a phase 1/2 clinical study to evaluate the safety and efficacy of SKB118 in participants with advanced solid tumors. The study includes a dose escalation stage, a dose expansion stage, and a indication expansion stage.

This is a multi-center, open-label, phase 1/2 clinical study to evaluate the safety, tolerability, pharmacokinetics (PK) characteristics, immunogenicity, and efficacy of SKB118 in participants with advanced solid tumors. The study includes a Phase 1 dose escalation stage, a Phase 1 dose expansion stage, and a Phase 2 indication expansion stage.

Inclusion Criteria:

1. Participants voluntarily joined this study and signed an informed consent form.
2. The age at the time of signing the informed consent form must be between 18 and 75 years.
3. Participants with histologically or cytologically confirmed advanced solid tumors who have failed standard therapy, have no standard therapy available, or are intolerant to standard therapy.
4. Participants should provide tumor tissue samples for biomarker testing as much as possible.
5. Researchers evaluated based on Response Evaluation Criteria in Solid Tumors(RECIST) Version 1.1 that there is at least one measurable lesion present.
6. Eastern Cooperative Oncology Group (ECOG) score is 0 or 1.
7. Expected survival period ≥ 12 weeks.
8. Participants have sufficient bone marrow, liver, kidney, and coagulation functions.
9. Male and female participants must agree to use highly effective contraceptive methods during the study period.

Exclusion Criteria:

1. Participants known to have meningeal metastasis, brainstem metastasis, spinal cord metastasis and/or compression, and active central nervous system (CNS) metastasis.
2. Patients with other malignant tumors within 3 years before the first administration.
3. There are serious heart or vascular diseases or high-risk factors present.
4. According to researchers' judgment, it is an uncontrollable systemic disease.
5. There are pleural effusion, pericardial effusion, or ascites with clinical symptoms or requiring repeated drainage (>1 time/week).
6. History of interstitial lung disease or non infectious pneumonia.
7. There are other lung diseases that may interfere with drug-related pulmonary toxicity.
8. There is a risk of developing esophagotracheal fistula or esophageal pleural fistula, or tumor invasion or compression of surrounding important organs and blood vessels accompanied by related clinical symptoms.
9. Screening imaging shows that the tumor encases important blood vessels or exhibits obvious necrosis or cavities, and the investigator determines that study enrollment would pose a risk of bleeding.
10. Previous or concurrent gastrointestinal perforation, surgical and wound healing complications, and bleeding events.
11. The toxicity of previous anti-tumor treatments has not been relieved, defined as the toxicity has not recovered to Common Terminology Criteria for Adverse Events (CTCAE) Version 6.0 grade 0 or 1.
12. Have experienced ≥ Grade 3 immune-related adverse events (irAEs) during prior immunotherapy.
13. Serious infection occurred within 4 weeks before the first administration.
14. Active hepatitis B or C, or simultaneous infection with Hepatitis B virus(HBV) and Hepatitis C virus(HCV).
15. Human immunodeficiency virus (HIV) test is positive or there is a history of acquired immunodeficiency syndrome (AIDS); Known active syphilis infection.
16. Known active pulmonary tuberculosis.
17. Known history of allogeneic organ transplantation or hematopoietic stem cell transplantation.
18. History of allergies to any components of SKB118 injection or severe hypersensitivity reactions to other monoclonal antibodies.
19. Having an active autoimmune disease that required systemic treatment within the past two years.
20. Active or prior history of confirmed inflammatory bowel disease.
21. Currently using or having recently used aspirin therapy.
22. Received oral or parenteral anticoagulants or thrombolytic agents within 2 weeks prior to the first dose.
23. Previous treatment with antibodies or drugs targeting T-cell co- stimulation or checkpoint pathways, as well as cell therapy.
24. Received chemotherapy, immunotherapy, biological therapy, or other large molecule anti-tumor drugs within 4 weeks before the first administration.
25. Within 6 months prior to the first administration, lung lesions received radiation therapy with a total dose greater than 30 Gray.
26. Have undergone major surgical procedures or suffered serious injuries within 4 weeks prior to the first administration of medication.
27. Those who have received treatment with other clinical investigational drugs within 4 weeks prior to their first administration.
28. Individuals who have previously received anti-tumor vaccines or have received any active vaccines within 4 weeks prior to their first treatment with the investigational drug.
29. Participants who received systemic corticosteroid therapy or other immunosuppressive drugs with>10 mg/day prednisone within 2 weeks prior to the first dose.
30. Pregnant or lactating women.
31. Participants with a known history of mental illness or substance abuse are unable to cooperate in completing the study.
32. Suffering from local or systemic diseases caused by non malignant tumors, or diseases or symptoms secondary to tumors, which may affect compliance.
33. Any condition that the researcher deems to interfere with the evaluation of the investigational drug, the safety of participants, or the interpretation of research results, or any other condition that the researcher deems unsuitable for participation in this study.