After years of speculation (and sly denials on the part of AMC), Robert Kirkman announced back in October that a character from The Walking Dead would finally cross over on to Fear the Walking Dead (or vice versa), though Kirkman would offer no details about who the character would be. There has been a lot of speculation since about who it could be, including Morales (who has since returned … and departed from The Walking Dead) and several other characters, like Luciana from Fear the Walking Dead.
Most of the speculation, however, has revolved around Abraham, thanks mostly to a tweet he delivered soon after the crossover announcement.
Truthfully, Abraham makes the most sense. He used to live in Houston, Texas, which is where Fear the Walking Dead will be relocating in its fourth season and since his character is dead on The Walking Dead, jumping to the companion series should not present any scheduling conflicts.