As a result you can play the game on PC and your Xbox One after a single purchase.
Sometime ago, when Xbox Play Anywhere was announced, Phil Spencer and other representatives of Microsoft confirmed that every first-party (and selected third-party) title will work with a cross-buy function for Xbox One and Windows 10.
It appears that not everyone in the web is convinced as there were various questions about Crackdown 3 and its support for XPA. It was (re-)confirmed by official Twitter account of Crackdown IP:
Crackdown 3 will indeed be a Play Anywhere title! https://t.co/radWMMG0KT
— Crackdown (@crackdown) May 23, 2017
Now we have to wait (probably) until E3 2017 to see any new footage from the game.