The seventh episode of the season (the second after Rick's exit) finds Paul "Jesus" Rovia (Tom Payne) and Tara Chamber (Alanna Masterson) in charge of the Hilltop community after the six-year time jump into the future. Some unknown conflict has caused a schism between Hilltop and Alexandria, the latter led by Michonne (Dania Gurira), who presumes that Maggie's been living at Hilltop.
When Michonne voices her shock at Maggie's absence, Siddiq (Avi Nash) reveals that Maggie left Hilltop with her son Hershel and is helping some far-flung community with do-gooder/civilization restarter Georgie (Jayne Atkinson), a character introduced briefly last season roaming the countryside looking to trade intel for records. Maggie is sending letters back to keep in touch, though she's apparently "happy" on her offscreen mission.
Though we don't actually know which mystery community Maggie is living in, comic fans expect it will likely be the massive Commonwealth, a city of 50,000 human survivors that has a football stadium at its disposal. The new community is a major factor in the current comic run, with the residents there living lives as close to normal as we've seen in the post-apocalypse, with restaurants, entertainment, and electricity at their disposal. Though, this being TWD, there's apparently some nefarious stuff bubbling under the surface.
Earlier this year, it was announced that Cohan wanted to pursue other projects like ABC's spy agency dramedy, Whiskey Cavalier, which premieres in 2019. Nevertheless, she is expected to make a return for the 10th season or, at the very least, cross over into a movie or two (especially if Maggie eventually runs across the long-lost Rick at that mystery community).