A Study of BL-B16D1 in Patients With Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma and Other Solid Tumors

Inclusion Criteria: 1. Sign the informed consent form voluntarily and follow the protocol requirements; 2. Gender is not limited; 3. Age: ≥18 years old and ≤75 years old (phase Ia); ≥18 years old (phase Ib); 4. Expected survival time ≥3 months; 5. Patients with pathologically and/or cytologically confirmed recurrent or metastatic head and neck squamous cell carcinoma and other solid tumors who failed or could not receive standard treatment; 6. Agreed to provide primary tumors or metastases 3 years archive of tumor tissue samples or fresh tissue samples; 7. Must have at least one accord with RECIST v1.1 define measurable lesions; 8. ECOG physical status 0 or 1; 9. The toxicity of previous antineoplastic therapy has returned to ≤ grade 1 as defined by NCI-CTCAE v5.0; 10. No severe cardiac dysfunction, left ventricular ejection fraction ≥50%; 11. The organ function level must meet the requirements if the patient has not received blood transfusion or hematopoietic stimulating factor therapy within 14 days before screening; 12. Blood coagulation function: international standardization ratio (INR) 1.5 or less, and the part activated clotting time (APTT) live enzymes ULN 1.5 or less; 13. Urinary protein ≤2+ or ≤1000mg/24h; 14. For premenopausal women with childbearing potential, a pregnancy test must be performed within 7 days before starting treatment, serum pregnancy must be negative, and the patient must not be lactating; All the patients (no matter male or female) shall be 6 months after the end of the treatment period and adequate precautions. Exclusion Criteria: 1. Antineoplastic therapy within 4 weeks or 5 half-lives before the first dose; Mitomycin and nitrosoureas were administered within 6 weeks before the first dose; Oral drugs such as fluorouracil; 2. History of severe heart disease; 3. QT prolongation, complete left bundle branch block, III degree atrioventricular block; 4. Active autoimmune and inflammatory diseases; 5. Before the first delivery within 5 years diagnosed as other malignant tumor; 6. Hypertension poorly controlled by two antihypertensive drugs (systolic blood pressure \> 150 mmHg or diastolic blood pressure \> 100 mmHg); 7. Patients with poor glycemic control; 8. Present with grade ≥1 radiation pneumonitis according to the RTOG/EORTC definition; Previous history of ILD or current ILD, or suspicion of such disease during screening; 9. Complicated with pulmonary diseases leading to clinically severe respiratory function impairment; 10. There is activity of the central nervous system symptoms; 11. Patients with a history of allergy to recombinant humanized or human-mouse chimeric antibodies or to any of the excipients of BL-B16D1; 12. Before transplant or allogeneic hematopoietic stem cell transplantation (Allo - HSCT); 13. Previous anthracycline-based adjuvant therapy (new), the cumulative dose anthracycline-based drugs \> 360 mg/m2; 14. Human immunodeficiency virus antibody positive, active tuberculosis, active hepatitis B virus infection or active hepatitis C virus infection; 15. Severe infection occurred within 4 weeks before the first dose; Signs of pulmonary infection or active pulmonary inflammation within 2 weeks before the first dose; 16. Patients with massive or symptomatic effusions or poorly controlled effusions; 17. Had participated in another clinical trial within 4 weeks before the first dose (calculated from the time of the last dose); 18. Had the following ocular diseases: a. active infection or corneal ulcer; b. monocular vision; c. a history of corneal transplantation; d. Contact lens dependence; e. Uncontrolled glaucoma; f. Uncontrolled or progressive retinopathy, wet macular degeneration, etc.; 19. Other circumstances that the investigator deemed inappropriate for participation in the trial.