After a few good Zombies in Spaceland (1980's), Rave in the Redwoods (1990's), and the coming Shaolin Showdown (1970's).
It would behoove Infinite Warfare Zombies to avoid the obvious 1950's,1960's,2000's or present day zombies and go way off the script with something unexpected.
Maybe try other movie cliches like a Robin Hood era or Roman Gladiator era or a semi redundant theme of Giant Monster movies (Godzilla/King Kong).
According to rumors, DLC 3 Zombies may take place in the 50s and may feature Kaiju-like monsters. Plus, the ending of Shaolin Shuffle hinted at a black and white scenery and tone. So we'll see but take all of that with a grain of salt
Gotta say that after playing all of them I actually like the latest one the best, for both zombies and multiplayer. Zombies is much harder here than Harlem or Cabin but the vibe and theme and map is pretty cool and man is it challenging. Lots of surprises and a sweet random gun to find.