To assess the safety and tolerability, obtain the recommended phase 2 dose (RP2D)/optimal biologic dose (OBD) and/or Maximum Tolerated Dose (MTD) for LM-24C5 in subjects with advanced solid tumors.

Inclusion Criteria:

1. Subjects who are fully informed of the purpose, nature, method and possible adverse reactions of the study, and are willing to participate in the study and sign the informed consent form (ICF) prior to any study related procedures.
2. Aged ≥18 years old when sign the ICF, male or female.
3. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1, and no deterioration within 2 weeks prior to the first dose.
4. Life expectancy ≥ 3 months.
5. Subjects must have histological or cytological confirmation of recurrent or refractory advanced solid tumors, and have progressed on standard therapy, or are intolerable for available standard therapy, or there is no available standard therapy.
6. Formalin-fixed paraffin-embedded (FFPE) tumor tissue samples meet the minimum requirements.
7. At least one measurable lesion according to RECIST v1.1.
8. Subjects must show appropriate organ and marrow function in laboratory examinations within 7 days prior to the first dose.
9. Subjects who are able to communicate well with investigators and understand and adhere to the requirements of this study.

Exclusion Criteria:

1. Participate in any other clinical trial within 28 days prior to 1st dosing of LM-24C5.
2. Any prior treatments towards the investigational target.
3. Subjects with anti-tumor treatment within 21 days prior to 1st dosing of LM-24C5, including radiotherapy, chemotherapy, biotherapy, endocrine therapy and immunotherapy, etc. the following treatments have different time limits.
4. Any adverse event from prior anti-tumor therapy has not yet recovered to≤ grade 1 of CTCAE v5.0.
5. Subjects with uncontrolled pain.
6. Subjects with known central nervous system (CNS) or meningeal metastasis.
7. Subjects who have uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures.
8. Subjects who experienced grade 3 or higher hypersensitivity to the treatment that contains any monoclonal antibody.
9. Subjects who take systemic corticosteroids (> 10 mg daily prednisone equivalents) or other systemic immunosuppressive medications within 2 weeks prior to the first dosing of LM-24C5.
10. Subjects with the known history of autoimmune disease.
11. Subjects with the history of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening chest CT scan.
12. Use of any live attenuated vaccines within 28 days prior to 1st dosing of LM-24C5.
13. Subjects who are taking therapeutic doses of anticoagulants such as heparin or vitamin K antagonists for presence of active thromboembolic disease.
14. Subjects who received major surgery or interventional treatment within 28 days prior to 1st dosing of LM-24C5.
15. Subjects who have severe cardiovascular disease.
16. Subjects who have uncontrolled or severe illness, including but not limited to ongoing or active infection
17. Subjects who have a history of immunodeficiency disease, including other acquired or congenital immunodeficiency diseases, or organ transplantation, or allogeneic bone marrow transplantation, or autologous hematopoietic stem cell transplantation.
18. HIV infection, active infection including tuberculosis, HBV and HCV infection, with the exception:
19. Subjects who have other active malignancies which are likely to require the treatment.
20. Child-bearing potential female who have positive results in pregnancy test or are lactating.
21. Subjects who have psychiatric illness or disorders that may preclude study compliance.
22. Subject who is judged as not eligible to participate in this study by the investigator.