Moments ago, the Microsoft Store listed the download size for Call of Duty: Black Ops 3. It looks like the game will require about 45GB of storage space on the Xbox One. I would assume that the PlayStation 4 version is also about the same size.

[ATTACH=CONFIG]1693[/ATTACH]

It does not look like the size is still up on the Xbox page, at least for the US store.

(Image and info via NeoGAF)