This study is testing two treatments for specific types of breast cancer. It compares the safety and effectiveness of one treatment using drugs called Dato-DXd and durvalumab, against another using pembrolizumab and chemotherapy. Both treatments are for people with certain types of breast cancer that haven't been treated before. The study helps to find out which treatment works best by measuring outcomes like **pCR** (pathologic complete response, meaning no cancer is found after treatment) and **EFS** (event-free survival, meaning no cancer events like growth or spread after treatment). To join, you need to be 18 or older, have specific types of breast cancer, and meet health requirements. You can't join if you’ve had other serious health issues or specific infections like hepatitis or HIV that is not controlled.

• Study includes several visits and monitoring over time.
• Participants may receive compensation for their time and travel.
• Potential risks include side effects from treatments like fatigue or nausea.