Chaos Space Marines are getting supplements for all of the major traitor legions.
These will be more and more complex as time goes on (as will all supplements) and are ordered based around how much they affect the game/core codex, and not based on anything else primarily.
World Eaters, Thousand Sons, Death Guard, Emperor's Children, Iron Warriors, Alpha Legion, Word Bearers and Night Lords will all get their due treatment and be fleshed out into characterful factions.
Keep in mind that though mono-god Legions are coming, it's very much so desired by essentially everyone, but it's being handled carefully.
Warzones however we're going to start seeing a lot more of, which will coincide with codex launches or between them to bridge codexes together (expect one for Tyranids and Ultramarines).
Also, despite being in the core codex, Space Marines will also be seeing Chapter Supplements to help deviate them farther.