Night Shift requires macOS Sierra 10.12.4 and one of these Mac computers,
using the built-in display or the displays listed:
• MacBook (Early 2015 or newer) • Apple LED Cinema Display
• MacBook Air (Mid 2012 or newer) • Apple Thunderbolt Display
• MacBook Pro (Mid 2012 or newer) • LG UltraFine 5K Display
• Mac mini (Late 2012 or newer) • LG UltraFine 4K Display
• iMac (Late 2012 or newer)
• Mac Pro (Late 2013 or newer)
So this doesn't work on arbitrary 3rd party displays, only Apple ones. That's a pretty big constraint. Edit: Some people are saying it works on their 3rd party monitors anyway.
Source: https://support.apple.com/en-ca/HT207513