On the r/CODZombies Reddit, u/LackingAGoodName was able to find the official description for Call of Duty: Black Ops 3 Zombies Chronicles in the Message of the Day files in the game after the latest update.
Here’s the official description found in the files:
Includes 8 classic remastered maps for Call of Duty® Zombies: World at War, Call of Duty®: Black Ops and Call of Duty®: Black Ops II. Complete original saga maps remastered in HD available on Call of Duty®: Black Ops III.
Experience the remastered zombie collection and experience the undead story first on PS4™.
Activision has still not officially announced Zombies Chronicles. An announcement is expected May 4 at 10AM PT.