A Study of BL-B01D1+PD-1 Monoclonal Antibody in Patients With Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma and Other Solid Tumors

Inclusion Criteria: 1. Subject volunteered to participate in the study and signed an informed consent; 2. Male or female aged ≥18 years and ≤75 years; 3. Expected survival time ≥3 months; 4. ECOG score 0-1; 5. Patients with recurrent or metastatic head and neck squamous cell carcinoma (non-nasopharyngeal carcinoma) and other solid tumors confirmed by histopathology and/or cytology; 6. Patients must provide a documented tumor tissue specimen of the primary or metastatic tumor within 3 years for PD-L1 testing and other testing; 7. At least one measurable lesion meeting the RECIST v1.1 definition was required; 8. No blood transfusion and 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; 9. The toxicity of previous antineoplastic therapy has returned to ≤ grade 1 as defined by NCI-CTCAE v5.0; 10. For premenopausal women of childbearing potential, a pregnancy test must be performed within 7 days before the initiation of treatment, a 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. Prior treatment with an ADC drug with TOP I inhibitors as a toxin; 2. Before the first delivery within four weeks or five half-life used anti-tumor treatment; Palliative radiotherapy was given within 2 weeks before the first dose; 3. Received any previous systemic antitumor regimen for solid tumors such as recurrent or metastatic head and neck squamous cell carcinoma; 4. Had received immunotherapy and developed ≥ grade 3 irAE or ≥ grade 2 immune-related myocarditis; 5. Use of an immunomodulatory drug within 14 days before the first dose of study drug; 6. Systemic corticosteroids were required within 2 weeks before the first dose of the study; 7. Has a history of severe disease of heart head blood-vessel; 8. Active autoimmune and inflammatory diseases; 9. Other malignant tumors that progressed or required treatment within 3 years before the first dose; 10. With ILD requiring steroid treatment, current ILD, or suspected ILD at screening; 11. Presence of: a) poorly controlled diabetes mellitus before study treatment; b) poorly controlled hypertension; c) history of hypertensive crisis or hypertensive encephalopathy; 12. Unstable thrombotic events requiring therapeutic intervention within 6 months before screening; 13. Patients with active central nervous system metastasis; 14. Patients with pleural effusion, pericardial effusion or ascites with clinical symptoms or requiring repeated drainage; 15. Had allergic history to recombinant humanized antibody or human-mouse chimeric antibody or to any of BL-B01D1's excipients; 16. Prior organ transplantation or allogeneic hematopoietic stem cell transplantation (Allo-HSCT); 17. Human immunodeficiency virus antibody positive, active tuberculosis, active hepatitis B virus infection or active hepatitis C virus infection; 18. Active infection requiring systemic therapy; 19. Had participated in another clinical trial within 4 weeks before the first dose; 20. Who have a history of psychotropic drug abuse and cannot abstain from it or have mental disorders; 21. Other circumstances that the investigator deemed inappropriate for participation in the trial.