This one’s gonna hurt if you liked South Park: The Stick of Truth: Obsidian, the games’ developer, currently has no plans to release DLC.
However there’s still a faint possibility for it. The team at Obsidian recently spoke with Polygon about planned discussions they have had with Ubisoft concerning if South Park: The Stick of Truth will have DLC:
As far as we know [Ubisoft and South Park] are done. We had always talked about it, extending the story through DLC, it was just stuff on paper. But it never went beyond talking about it. That was when THQ was involved. When it moved to Ubisoft, there was more pressure to get it done. I think that became the priority, so we got it done.
So any plans for South Park: The Stick of Truth DLC are not in the plans for the future.