Battle Royale won't be available for Call of Duty: Modern Warfare's launch, as the developers at Infinity Ward said they are focused on delivering 'core multiplayer first.
However, that is not to say Battle Royale is never happening. In fact, content creator LongSensation recently shared a rumor he heard about the mode launching in early 2020 as a free and separate download from the main game.
So apparently Battle Royale in #ModernWarfare will be a free mode to release in early 2020. It will be downloadable as a separate game, but also will still be connected to the core game. If this is true then it's a very good move by Activision.
Likely the intro will be "INFINITY WARD" "RAVEN SOFTWARE" "ACTIVISION" then a loading screen taking you to the main menu for Battle Royale.
Of course, this is far from official confirmation at this point, but we'd be truly surprised if Activision didn't push Infinity Ward to make a Battle Royale mode for Call of Duty: Modern Warfare as well, even with Black Ops 4's Blackout mode still very much alive.
Modern Warfare is out on October 25th for PC, PlayStation 4 and Xbox One, featuring cross-play for the first time in the franchise.