Some Windows 10 users have reported seeing ads for Rise of the Tomb Raider with links to Windows Store from where users can purchase the video game. Microsoft started selling the game last month. The advertisements are because of the Windows Spotlight feature in your Personalization settings. If you don’t want to see these intrusive ads, follow the steps given below to disable Windows Spotlight. The good news is that you can turn the ads OFF. The ads are turned ON for your lock screen by default, which is definitely a clever way to offer companies to reach their customers.
Source: https://thehackernews.com/2016/02/windows10-lock-screen-ads.html