A new DLC with a new story, followed by returning weapons and vehicles and some new. New gameplay with the return of sasquatch hunts, and some new side quests, along with a story quest.
Takes place in a city similar to State of decay:Lifeline. Where the city is overwhelmed with blood plague. (Example as seen in State of decay 2: Daybreak) You play as local survivors, rescuing people and building a community. You are then sent out to recruit a new military survivor, he tells he has been separated from his squad in pursuit to find the source of the blood plague. They belive CLEO's involvement might have something to do with the blood pleague pandemic. The stage is set, you and your community will have to fight to discover the truth, and essentially save the city.
The DLC would come with new weapons, vehicles, base mechanics, characters, and a few zombie threats, maybe even a zombie boss. You can also play the game even After you have completed the main story quests. The city won't clean itself up.
After you beat the game, there could be some more story quests, and some side quests for certain characters. Nothing major, but some closure after such and event would calm, and players will remain to build thier communities after the main story is beaten.
I think this would be a great addition to the game, players would enjoy hearing from sasquatch again, and would be a change in scenery, from being out in the country, to the streets of a fallen city. It would be great to have more quests to do instead of the same cycle of gaining supplies and thriving. I think the stage for this DLC is already set, however I'm not a writer for the game itself, but I do think that this idea would definitely be a great addition to both the game and the fans of this community.