Quantum Break is a standard Xbox Play Anywhere title. This means buying it once on the Xbox Store does not automatically grant you the PC version (and vice versa) under normal circumstances.
Your progress, achievements, and Gamerscore sync via the cloud as long as you use the same Microsoft account. quantum break cross buy
The Steam version of Quantum Break does not support cross-saves with the Xbox console version. 🎮 How to Play on Both Today Quantum Break is a standard Xbox Play Anywhere title
Despite not being cross-buy, the game does support functionality between the Xbox console and the Microsoft Store/Xbox App version for PC. quantum break cross buy