The goal of this study aims to evaluate the efficacy and safety of QLS1317 in patients with MSI-H/dMMR advanced solid tumors who failed standard treatment.

Inclusion Criteria:

-1. Males or females aged ≥ 18 at the time of signing the informed consent form (ICF).

2. Expected survival duration ≥ 3 months. 3. Participants with advanced solid tumors of MSI-H/dMMR who have failed standard treatment.

4. At least one measurable lesion according to RECIST v1.1. 5. Eastern Cooperative Oncology Group (ECOG) physical performance status score of 0-1.

6. Patients with sufficient organ function.

Exclusion Criteria:

• 1. Have a history of allergy to any component of the study drug. 2. Oral medication is not allowed. 3. The residual toxic reactions caused by previous anti-tumor treatment are higher than Grade 1 according to CTCAE v6.0.

  4. Known or discovered during screening period to have active central nervous system metastasis.

  5. Having suffered from other malignant tumors within 5 years prior to the first dose.

  6. The presence of uncontrollable pleural effusion, pericardial effusion, or ascites that require drainage or treatment.

  7. Chronic active hepatitis B, active hepatitis C, or human immunodeficiency virus (HIV) infection.

  8. Suffering from severe cardiovascular and cerebrovascular diseases. 9. Any severe or uncontrollable systemic disease. 10. Have received allogeneic tissue/solid organ transplantation.