The failed cure to the zombie virus in Fear the Walking Dead season 8 supports theories of a crossover between the various shows in The Walking Dead universe. For a long time, it’s been suspected that the franchise is gradually building up to a storyline that unites its biggest characters, who have been drifting apart for years now. So many are currently on different paths, but certain circumstances could always bring them back together again, perhaps to combat a common enemy.

https://screenrant.com/fear-the-walking-dead-june-crm-capture-theory/