This is an open label, multi-center, multiple dose Phase I study to evaluate the safety, tolerability, pharmacokinetics and efficacy of SHR-3821 injection in subjects with advanced solid tumors.

Inclusion Criteria:

1. Voluntary participation and written informed consent.
2. 18-75 years older, no gender limitation.
3. Eastern Cooperative Oncology Group (ECOG) score: 0-1.
4. With a life expectancy ≥ 3 months.
5. Pathologically diagnosed advanced solid tumor.
6. Be able to provide fresh or archived tumour tissue.
7. At least one measurable lesion according to RECIST v1.1.
8. Adequate bone marrow reserve and organ function.
9. Contraception is required during the trial.

Exclusion Criteria:

1. Meningeal metastasis history or clinical symptoms of central nervous system metastasis.
2. Uncontrollable tumor-related pain.
3. Uncontrolled pleural effusion, pericardial effusion, or abdominal effusion with clinical symptoms.
4. Received systemic antitumor therapy before the first dose.
5. Treated with similar target therapy as SHR-3821 before the first dose.
6. Received systemic anticancer treatments 4 weeks prior to the initiation of the study treatment.
7. Unresolved CTCAE 5.0>=grade 2 toxicities from previous anticancer therapy.
8. Current or History of ILD.
9. Active severe digestive disease.
10. Previous or co-existing malignancies.
11. History of severe hypersensitivity reactions to either the drug substances or inactive ingredients of SHR-3821.
12. Active hepatitis B or active hepatitis C.
13. Other inappropriate situation considered by the investigator.