Your PC is being monitored and protected.
That's what it literally says in the Windows 10 security/privacy settings.
Whether intended or not, I get extremely scary vibes from hearing that my PC is "being monitored". I know they (likely) mean that the Windows Defender (or whatever it's called this week) is locally checking any new binary files being executed, but it sounds really creepy, especially as I've gone out of my way to turn off anything that can be turned off which in any way uses the network connection in any way for any purpose other than what I actively and consciously do.
Why would they pick such a phrase? Are they so completely and totally tone-deaf to the users' need for security and privacy that they think that this is perceived as something positive?