Microsoft is investigating a known issue affecting the new Chromium-based Edge browser where the app is automatically launching itself on Windows startup even if users haven’t configured it to auto-start after their systems boot up. Microsoft has also recently started showing Microsoft Edge advertisements every time users are searching for competing browsers and, at the moment, there is no way to stop this behavior. Microsoft also announced on June 3 that the new Edge web browser has started rolling out automatically via Windows Update to all customers using Windows 10 1803 or later.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-investigating-edge-self-launch-on-windows-startup/