This is a Phase 1, open-label, multicenter, dose escalation study of HY1272 (administered via IV) evaluating both Single Ascending Dose (SAD) and Multiple Ascending Dose (MAD) in patients diagnosed with locally advanced or metastatic solid tumors (monotherapy) or locally advanced or metastatic EGFRm+ NSCLC (combination therapy). The study is designed to evaluate safety, tolerability, PK, and anti-tumor activity of HY1272 administered once weekly. Patients in the monotherapy portion of this study will receive only HY1272. Patients in the combination therapy portion of this study will receive osimertinib administered once daily (QD) with HY1272.