Windows 10 is grayscale and color filters are off

So I was working on Windows 10, and my screen suddenly went from color to grayscale. I looked it up and all the websites mentioned the color filter and the respective shortcut (Control+Windows+C). When looking at the color filter setting though, the color filter is off. If I log out, then the login screen is also grayscale before briefly flashing color when logging in. Can anybody help me figure this out?

Win+End worked for me. CTRL+Win+C did not work.

You probably have f.lux installed on your computer. The software has a grayscale feature which is toggled using the shortcut Win+End. Try pressing it again to turn it off.