This study adopts a multi-center, open-label, non-randomized trial design. It plans to enroll patients with Advanced solid tumor. Dose-escalation and PK-expansion studies will be carried out to evaluate the safety, tolerability, and preliminary efficacy of sirolimus (albumin-bound) in combination with Different ADCs (DP303c/SYS6043/SYS6002/SYS6010) in this patient population, and to confirm the recommended phase 2 dose (RP2D).

Inclusion Criteria:

• 1. Subjects aged 18 to 75 years (inclusive).
• 2. Patients with advanced solid tumors that are unresectable or metastatic and confirmed by histology or cytology.
• 3. At least one measurable lesion, as defined by RECIST 1.1 criteria.
• 4. ECOG performance status of 0 or 1.
• 5. Expected survival ≥ 3 months.
• 6. Adequate function of major organs and bone marrow.
• 7. Willing to provide samples of previously removed tumors or undergo fresh tumor biopsy.
• 8. Women or man of childbearing potential must use highly effective contraception.
• 9. Able to understand and voluntarily sign the written informed consent form (ICF).

Exclusion Criteria:

• 1. Previous use of antibody-conjugated drugs with similar loading agents for treatment.
• 2. Previous anti-tumor treatment drugs were not adequately removed.
• 3. Active leptomeningeal disease or uncontrolled CNS metastasis.
• 4. Having a history of severe or uncontrolled cardiovascular or cerebrovascular diseases.
• 5. Previous interstitial lung disease requiring glucocorticoid treatment, Or currently suffering from interstitial lung disease/non-infectious pneumonia, or the imaging examination during the screening period cannot rule out interstitial pneumonia/lung disease.
• 6. Patients who developed severe and moderately severe lung diseases that significantly affected lung function within 6 months of the first medication administration; patients requiring supplementary oxygen therapy.
• 7. Individuals who currently have eye diseases such as corneal disorders, retinal disorders, or active ocular infections that require intervention, or who have a history of serious corneal-related eye diseases in the past; or who are unwilling to stop wearing corneal contact lenses during the study; or who have other existing eye diseases that affect the assessment of ocular toxicity after the administration of the investigational drug.
• 8. Currently suffering from skin diseases that require oral or intravenous medication treatment.
• 9. Had a history of ulcerative colitis or Crohn's disease.
• 10. Within 14 days prior to the first administration of the medication, there is a need for systemic antibacterial, antifungal or antiviral treatment for severe chronic or active infections, and there is no cure for active tuberculosis.
• 11. Known to be allergic to any component of the test drug, or allergic to the humanized monoclonal antibody product.
• 12. Participants with poor compliance.