Microsoft is working on a new Windows security feature that'll automatically lock your computer when it detects you've stepped away. Called Dynamic Lock, the feature is present in Windows 10 test builds. It's easy to see how Windows Hello facial recognition could be used to detect inactivity. For other PCs, it's not clear how the feature functions.
Dynamic Lock may be useful in work environments where dozens of people are frequently leaving their PCs. They would no longer have to worry about manually locking their computer each time they go somewhere.
The feature will arrive with the Creators Update in April.