Windows 10 users in Germany are being shown ads in their default browser. The ads are being displayed in the ad-supported Windows 10 app. If you use a VPN to access the ads, the ads will not be shown in your browser. Instead, you will have to use the browser to see the ads and use an ad blocker to avoid the ads. For example, the adverts are not automatically shown in the browser, they are shown in an ad-only version of the app.
Source: https://www.bleepingcomputer.com/news/security/windows-10-apps-hit-by-malicious-ads-that-blockers-wont-stop/