Hello, welcome to Microsoft Answers Community. Yes. You will need a Microsoft Account to download games from Microsoft Store or Xbox, and play them in Online mode.
Pre-order or pre-purchase Call of Duty: Modern Warfare II on PlayStation 4, PlayStation 5, Xbox Series X|S / Xbox One, Battle PC or Steam PC and get early access to the Call of Duty: Modern Warfare II Open Beta. Stay tuned for more details about the content of the Open Beta.