The study is being conducted to evaluate the safety, tolerability and pharmacokinetics of SHR-4685 in participants with advanced solid tumors.

Inclusion Criteria:

1. Have fully understood this study and voluntarily signed the informed consent form, with good compliance and cooperation with follow-up;
2. Age 18-75 years, any gender;
3. Performance status ECOG score 0 or 1;
4. Expected survival time greater than 3 months;
5. Presence of at least one measurable lesion according to RECIST 1.1 criteria;
6. Have adequate organ function;
7. Female participants of childbearing potential must have a negative serum pregnancy test within 7 days prior to the first dose; and must not be lactating.

Exclusion Criteria:

1. Participants who have received any approved anti-tumor drugs (including investigational anti-tumor drugs) within 4 weeks prior to the first dose of the IP;
2. Toxicities from prior anti-tumor therapy have not recovered to ≤ Grade 1 or to the level specified in the inclusion/exclusion criteria;
3. Presence of central nervous system (CNS) metastases;
4. Concurrent active malignancy other than the primary tumor;
5. History of central nervous system diseases within 12 months prior to screening;
6. Participants who have undergone major surgery other than diagnostic or biopsy procedures within 28 days prior to the first dose, or who are expected to undergo major surgery during the study;
7. Participants with active tuberculosis or a history of active tuberculosis infection within ≤48 weeks prior to screening, regardless of treatment;
8. Presence of any significant clinical or laboratory abnormality that, in the investigator's opinion, affects safety evaluation;
9. History of deep vein thrombosis or pulmonary embolism within 6 months prior to screening;
10. Uncontrolled pleural effusion, pericardial effusion, or ascites requiring clinical intervention;
11. Positive for human immunodeficiency virus (HIV) (HIV1/2 antibodies) with CD4+ T lymphocyte count <350 cells/uL; or history of other acquired/congenital immunodeficiency diseases; or history of allogeneic bone marrow or solid organ transplantation;
12. Active chronic hepatitis B or active hepatitis C;
13. Known history of hypersensitivity to any component of the formulations used in the study;
14. Other factors, in the opinion of the investigator, that may affect the study results or result in forced halfway termination of this study, such as alcoholism, drug abuse, suffering from other serious diseases (including psychiatric disorders) requiring concomitant treatment, seriously abnormal laboratory test values, family or social factors and other conditions that may affect the safety of the patient or collection of study data.