A Study of BL-B01D1+PD-1 Monoclonal Antibody in Patients With Unresectable Locally Advanced or Recurrent Metastatic Triple-negative Breast Cancer

Inclusion Criteria: 1. Voluntarily sign the informed consent and follow the requirements of the protocol; 2. Age: ≥18 years old and ≤75 years old; 3. Expected survival time ≥3 months; 4. ECOG 0 or 1; 5. Subjects with histologically and/or cytologically confirmed, inoperable locally advanced or recurrent or metastatic triple-negative breast cancer; 6. Patients should not have received previous systemic therapy for unresectable, locally advanced, recurrent, or metastatic triple-negative breast cancer; 7. A archived tumor tissue specimen or fresh tissue specimen of the primary or metastatic lesion within 2 years must be provided; 8. Must have at least one place in accordance with RECIST v1.1 define measurable lesions; 9. No blood transfusion, no use of cell growth factors and/or platelet raising drugs within 14 days before screening, and the organ function level must meet the requirements; 10. Toxicity of previous antineoplastic therapy has returned to ≤ grade 1 defined by NCI-CTCAE v5.0; 11. For premenopausal women with childbearing potential, a pregnancy test must be performed within 7 days before the initiation of treatment, the serum or urine pregnancy test must be negative, and the patient must not be lactating; All enrolled patients should take adequate barrier contraception during the entire treatment cycle and for 6 months after the end of treatment. Exclusion Criteria: 1. ADC drugs that have received topoisomerase I inhibitors as small molecule toxins; 2. Palliative radiotherapy within 2 weeks before the first dose; 3. Patients with checkpoint inhibitors prior to neoadjuvant/adjuvant chemotherapy; 4. Use of an immunomodulatory drug within 14 days before the first dose of study drug; 5. The history of severe cardiovascular and cerebrovascular diseases in the past six months was screened; 6. QT prolongation, complete left bundle branch block, III degree atrioventricular block, frequent and uncontrollable arrhythmia; 7. Active autoimmune and inflammatory diseases; 8. Receiving long-term systemic corticosteroid therapy, etc., before the first dose; 9. Other malignant tumors that progressed or required treatment within 5 years before the first dose; 10. Presence of: a) poorly controlled diabetes mellitus before starting study treatment; b) severe complications associated with diabetes mellitus; c) a glycated hemoglobin level of 8% or more; d) hypertension poorly controlled by two antihypertensive drugs; e) history of hypertensive crisis or hypertensive encephalopathy; 11. Present grade ≥2 radiation pneumonitis according to the RTOG/EORTC definition; Patients with current ILD; 12. Complicated with pulmonary diseases leading to clinically severe respiratory impairment; 13. 6 months prior to screening needs treatment intervention unstable thrombotic events; 14. Patients with active central nervous system metastases; 15. Patients with massive or symptomatic effusions or poorly controlled effusions; 16. Allergic history to recombinant humanized antibody or human-mouse chimeric antibody or allergic to any excipients of the test drug; 17. Prior organ transplantation or allogeneic hematopoietic stem cell transplantation; 18. HIV antibody positive, active tuberculosis, active hepatitis B virus infection, or active hepatitis C virus infection; 19. Serious infection within 4 weeks before the first dose of study drug; Signs of pulmonary infection or active pulmonary inflammation within 4 weeks; 20. Participated in another clinical trial within 4 weeks before the first dose; 21. Patients with superior vena cava syndrome should not be rehydrated; 22. Have a history of psychotropic substance abuse with an inability to quit or a history of severe neurological or psychiatric illness; 23. Imaging examination showed that the tumor had invaded or wrapped the large thoracic vessels; 24. Serious unhealed wound, ulcer, or fracture within 4 weeks before signing the informed consent; 25. Clinically significant bleeding or obvious bleeding tendency within 4 weeks before signing the informed consent; 26. Subjects who are scheduled to receive live vaccine or receive live vaccine within 28 days before the first dose; 27. Other circumstances considered by the investigator to be inappropriate for participation in the trial.