The Walking Dead franchise appears to afraid to use the Commonwealth, so it's been substituting that community with other organizations. In the last year, two expansive, powerful organizations have been established in The Walking Dead universe: the Pioneers and the mysterious CRM organization that's associated with the black helicopter. So far, the franchise has steered away from the Commonwealth - the biggest (and most important) community in the comics - since it appears the series' producers are hesitant to dive into the storyline, but why?
Introduced toward the end of The Walking Dead comic book series, the Commonwealth is an enormous, thriving network of communities that consists of 50,000 survivors. They came into the story near the conclusion of the Whisperer War. They live by a class system that divides people by who they were before the apocalypse. The rich remain rich, and the poor remain poor. The Commonweath's way of doing things is a divisive subject for the survivors, as some are vehemently against it. In any case, the Commonwealth, whose main goal is to rebuild society into what it once was, changed the direction of the comic and remained an important part of the story until The Walking Dead officially ended in summer 2019.
Organizations with goals similar to the Commonwealth are already present in the TV side of The Walking Dead universe. The CRM organization, which is responsible for kidnapping Rick Grimes (Andrew Lincoln), has been active in both shows, and is expected to be explored in The Walking Dead movies. Fear The Walking Dead is currently dealing with new villain Ginny (Colby Minifie) and the Pioneers. Neither organization is tied to the Commonwealth in any way. So AMC is using the Commonwealth's purpose in the comics on both shows but in different ways, and more importantly, without the Commonwealth itself.
CRM, the Pioneers, and the Commonwealth all have the intention to rebuild and expand. Improving society and making the world more like it was before the apocalypse are their primary goals. The fact that The Walking Dead universe is currently going through two very similar storylines makes it seem unlikely that a third organization with the same goal would be introduced some time soon. But it doesn't seem like that's the case. Currently, the Whisperers are the main concern on The Walking Dead, and Fear The Walking Dead is still several years behind the flagship show.
Instead of developing different ideas, the fact that both shows felt the need to still incorporate Commonwealth-esque storylines is unclear. One possible reason is that The Walking Dead actually is moving forward with the Commonwealth story, and that it will connect to the mysterious woman named George who befriended Maggie (Lauren Cohan) in season 8. Another possibility is that The Walking Dead is saving the Commonwealth for a future - or perhaps final - storyline. Since the Commonwealth story is where the comic book series came to an end, the TV show could move in the same direction.