Available at All platforms now. Enjoy :)
You need base game for Steam only to get this DLC but for other platforms you can have it without base game even via Epic games regardless of condition to have base game.
This content requires the base game Tom Clancy's Ghost Recon® Wildlands on Steam in order to play.
Get Tom Clancy's Ghost Recon® Wildlands - Fallen Ghosts
Free to keep when you get it before 12 Oct @ 4:00am.