Players of the Call of Duty: Modern Warfare beta are reporting being able to transfer their save progress between different platforms, including PS4 and Xbox, which would mean cross-save and progression is enabled.
We’ve known for a while that Modern Warfare has cross-play. This feature allows players to compete together online across the console divide, and anyone currently trying out the beta is able to team up regardless of platform.
But cross-progression is slightly different. It doesn’t just allow you to go a round in Team Deathmatch with a pal on another platform, it means you can swap and change between platforms without losing any progress or starting over from scratch. This is great for players, but platform holders have traditionally been reluctant to introduce such a feature because it makes it easier for players to defect to their rivals.
Source: IGN.com Players Report Cross-Save In The Call of Duty: Modern Warfare Beta