Bethesda recently revealed the details on their plans and pricing structure for Fallout 4's upcoming DLC content for the PlayStation 4, Xbox One and PC. Pete Hines, the Vice President of Marketing at Bethesda, has offered further details on which platforms would be getting exclusive access to the DLC.
@GabeCounts plan is for all platforms at once. no exclusives
— Pete Hines (@DCDeacon) February 16, 2016
That's right, Bethesda has not created a special alliance with any console manufacturer. The Fallout 4 DLC will be available across all platforms at the same time.
If you're interested in grabbing the DLC, you might want to check out the DLC beta sign-ups. If Bethesda picks you to test the upcoming DLC, you'll get all of the DLC for Fallout 4 for free.