Hope they kept Dogmeat in the new version.
They don’t. In fact, there are no companions whatsoever.
The premise is that there are no humans left alive in the game because they were all turned into zombies (scorched). An interesting idea, but it fails because one of the good things about Fallout is how the remaining humans survive day to day. Without that the game seems lifeless.
I would not be surprised if in 6 months to a year they pull a “Final Fantasy 14” and just completely redo the game, advancing it a few years in game time and bringing back Human NPCs.