Trusted Reviews has apparently received a "number of alleged development notes on Red Dead Redemption 2, that reveal gameplay details regarding missions, mechanics, online multiplayer modes, and story."
Having looked at these leaked notes, the feature that immediately jumped out at me was the Red Dead Redemption 2 battle royale mode. With PUBG and Fortnite really putting the battle royale game type on the map, I suppose I shouldn't be surprised to see it featured in this AAA title.
In addition to the Red Dead Redemption 2 battle royale mode, new "Revive and Survive," and "Money Grab" game types have been detailed:
Revive and Survive pits two teams against each other as they try and stay alive. You’ll have a limited amount of time to revive your teammates before they are eliminated.
Money Grab features two teams fighting to procure bags of money in a central location. You’re expected to collect and return them to your base as quickly as possible.
Other new features reportedly coming to Red Dead Redemption 2 are a first-person mode, which will work in multiplayer and single-player; player choices impacting the story, which can "lead to different mission outcomes, objectives, and dialogue;" and an improved online open world, that takes things even further than GTA Online.
While it's important to note that this leaked information could be false, it sounds pretty believable to me. I can definitely see Rockstar Games putting their own twist on a Red Dead Redemption 2 battle royale mode, and all of the other features are expected of a next-gen Red Dead title.