Phase Ib: Explore the safety and tolerability of BL-M07D1 to further define RP2D in a variety of solid tumors, including locally advanced or metastatic urinary and gastrointestinal tumors. Phase II: To explore the efficacy of BL-M07D1 in patients with a variety of solid tumors including locally advanced or metastatic HER2-positive/low-expressing urinary and gastrointestinal tumors.

Inclusion Criteria:

1. Voluntarily sign the informed consent form and comply with the protocol requirements;
2. No gender restrictions;
3. Age: ≥18 years and ≤75 years;
4. Expected survival time ≥3 months;
5. Patients with unresectable locally advanced or metastatic HER2-positive/low-expressing urological and digestive system tumors, as well as other solid tumors;
6. Agree to provide archived tumor tissue specimens or fresh tissue samples from primary or metastatic lesions within the past 2 years;
7. Must have at least one measurable lesion as defined by RECIST v1.1;
8. ECOG performance status score of 0 or 1;
9. Toxicity from prior anti-tumor therapy has recovered to ≤ Grade 1 as defined by NCI-CTCAE v5.0;
10. No severe cardiac dysfunction, with left ventricular ejection fraction (LVEF) ≥50%;
11. Organ function levels must meet the requirements;
12. Coagulation function: International Normalized Ratio (INR) ≤1.5, and activated partial thromboplastin time (APTT) ≤1.5 × ULN;
13. Urine protein ≤2+ or ≤1000 mg/24h;
14. Albumin ≥30 g/L;
15. For premenopausal women with childbearing potential, a pregnancy test (serum/urine) must be performed within 7 days before starting treatment, and the result must be negative; they must not be breastfeeding. All enrolled patients (regardless of gender) must use adequate barrier contraception throughout the treatment period and for 7 months after treatment ends.

Exclusion Criteria:

1. Received chemotherapy, biological therapy, immunotherapy, or other antitumor treatments within 4 weeks or 5 half-lives prior to the first dose;
2. Previously treated with ADC drugs containing camptothecin derivatives as payloads;
3. History of severe cardiovascular or cerebrovascular diseases;
4. Active autoimmune or inflammatory diseases;
5. History of other malignancies within 5 years prior to the first dose;
6. Thrombotic events requiring therapeutic intervention within 6 months before screening;
7. Patients with significant pleural/peritoneal/pelvic effusion or pericardial effusion, or those with symptomatic effusion, or poorly controlled effusion;
8. Poorly controlled hypertension despite antihypertensive medication;
9. Current interstitial lung disease, drug-induced interstitial pneumonitis, radiation pneumonitis requiring steroid treatment, or history of these conditions;
10. Patients with primary central nervous system (CNS) tumors or CNS metastases that failed local treatment;
11. History of hypersensitivity to recombinant humanized antibodies or human-mouse chimeric antibodies, or any excipients of BL-M07D1;
12. Previous organ transplantation or allogeneic hematopoietic stem cell transplantation;
13. Positive for human immunodeficiency virus (HIV) antibodies, active tuberculosis, or active hepatitis C virus (HCV) infection;
14. Active hepatitis B virus (HBV) infection (exclusion criterion);
15. Severe infection requiring systemic treatment within 4 weeks before the first dose of the study drug;
16. Participation in another clinical trial within 4 weeks before the first dose;
17. Pregnant or lactating women;
18. Any other condition deemed unsuitable for participation in this clinical trial by the investigator.