It aims to assess the safety, tolerability, pharmacokinetics, and preliminary antitumor activity of DB-1310 in subjects with advanced/unresectable, or metastatic NSCLC with or without EGFR active mutation, HER2 positive breast cancer, castration-resistant prostate cancer, head and neck squamous cell carcinoma. The gene discussed is ERBB2; the disease is head and neck squamous cell carcinoma.