While the original roadmap has long since been scrapped, the Valheim devs have not given up on the ideas they laid out back then. As such, the freshly released update brings with it many of the features that once belonged to the "Cult of the Wolf" section, including brand new instanced mini-dungeons by the name of Frost Caves.
The Frost Caves are similar to the Burial Chambers and Sunken Crypts that came before, and much like them offer you a chance to square off against new enemies, gather new resources, as well as collect new materials. Naturally, all of this will be going towards crafting a fancy new armor and weapon set!
These new enemies won't be exclusive to the Frost Caves, however, as there is also a new event that have them charging at you and your base. So if you do decide to go into the freshly updated Mountain biome, make sure to come prepared.
As for the future, the team is currently working on the sixth biome - the Mistlands. The details are still few and far between, but you can expect to see the usual stuff like new enemies and resources, as well as a chunky new boss to grind your axe against.
You can learn a little bit more about the Frost Caves update, as well as Valheim in general, over at Steam. Enjoy!