New Call Of Duty Games, stories, mechanics, characters! Fill me in?

So I straight up have not played a call of duty game in years. Last I remember, at all, was Black Ops II. Although that may have just been the various amounts of fond memories. I have no clue what's been going on with any of the call of duty series', can someone fill me in?

Two things I want to explain first, however:
1. I'm aware of Warzone, I've seen a lot about it, but that's about it. I haven't heard or seen much about any COD since about Black ops II. Which, leads me into my next point
2. I remember this really weird map from Black Ops II that never fit into the story of any other game. It may just be my hazy memory making things up, but I somewhat remember this old zombies map, like 1950s american style, with this red portal dimension (I guess similar to or an antithesis to the Origins Agartha) that had these giant Panzer-like bosses every few rounds. I don't think there were any DLC for zombies after Origins, however. Am I dreaming that this happened or have I got something wrong?

thanks man, this is a really good post!