Black Ops 4 is getting a Zombies mode, and some of it will be set on the Titanic. Also, zombie tigers? Is that a zombie goddamned tiger in the trailer above? It would appear so.
The trailer introduces the mode's four playable characters, and from what I can gather the narrator Scarlett Rhodes is chief among these. She's seeking ancient treasures, which take her to some pretty rough (and zombie infested) environs. In addition to the Titanic episode, which is called Voyage of Despair, there's also IX, which appears to be set in some kind of Roman colosseum environment. Whatever it is, you'll be shooting zombies in it. There's an older trailer here, which shows more footage of the same areas.
Call of Duty: Black Ops 4 releases October 12. There won't be a single-player mode, but there will be a Battle Royale mode.