Inclusion Criteria:
1. Voluntarily sign the informed consent form and comply with the protocol requirements;
2. Age: ≥18 years and ≤75 years;
3. Expected survival time ≥3 months;
4. Locally advanced or metastatic urothelial carcinoma and other solid tumors;
5. Agree to provide archived tumor tissue specimens or fresh tissue samples from the primary or metastatic lesion within 2 years;
6. Must have at least one measurable lesion as defined by RECIST v1.1;
7. Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1;
8. Toxicity from prior antitumor therapy has recovered to ≤Grade 1 as defined by NCI-CTCAE v6.0;
9. No severe cardiac dysfunction, with left ventricular ejection fraction ≥50%;
10. Organ function levels must meet the requirements;
11. Coagulation function: international normalized ratio ≤1.5, and activated partial thromboplastin time ≤1.5 ULN;
12. For premenopausal female trial participants of childbearing potential, a serum pregnancy test must be performed within 7 days before the start of treatment. The serum pregnancy test must exclude pregnancy, and the participant must not be breastfeeding; all enrolled trial participants and their partners must agree to use adequate highly effective contraceptive measures throughout the entire treatment period and for 7 months (women) and 4 months (men) after the end of treatment. It is recommended to also use other contraceptive methods, such as barrier contraception;
13. Trial participants are able and willing to comply with the visits, treatment plans, laboratory tests, and other study-related procedures specified in the study protocol.
Exclusion Criteria:
1. Received chemotherapy, targeted therapy, biological therapy, etc. within 4 weeks or 5 half-lives before the first dose;
2. History of severe heart disease;
3. Prolonged QT interval, complete left bundle branch block, third-degree atrioventricular block; frequent and uncontrollable arrhythmias;
4. Active autoimmune disease or inflammatory disease;
5. Diagnosed with other malignancies within 5 years before the first dose;
6. Unstable thrombotic events requiring therapeutic intervention within 6 months before the first dose;
7. Hypertension poorly controlled by two antihypertensive drugs;
8. Patients with poorly controlled blood glucose;
9. History of interstitial lung disease requiring hormone therapy, or current ILD or grade \>= 2 radiation pneumonitis;
10. Concurrent lung disease causing clinically severe impairment of respiratory function;
11. Active central nervous system metastasis;
12. Patients with a history of allergy to recombinant humanized antibodies or human-mouse chimeric antibodies, or allergy to any excipient of BL-M09D1;
13. Previous organ transplantation or allogeneic hematopoietic stem cell transplantation;
14. Positive human immunodeficiency virus antibody, active tuberculosis, active hepatitis B virus infection, or active hepatitis C virus infection;
15. Active infection requiring systemic treatment within 4 weeks before the first study drug administration;
16. Pleural, abdominal, pelvic effusion, or pericardial effusion requiring drainage and/or accompanied by symptoms within 4 weeks before the first study drug administration;
17. Participated in another clinical trial within 4 weeks or 5 half-lives before the first dose;
18. Trial participants with clinically significant bleeding or a clear bleeding tendency within 4 weeks before the first study drug administration;
19. Inflammatory bowel disease with symptoms or requiring drug intervention, or partial or complete intestinal obstruction, within 4 weeks before the first study drug administration;
20. Known mental illness or disorder that may affect trial compliance;
21. Trial participants planning to receive vaccination or who received a live vaccine within 28 days before the first dose;
22. Pregnant or breastfeeding women;
23. Other circumstances in which the investigator considers the patient unsuitable for participation in this clinical trial.
