Both Ziva and Tony returned to MCRT, but Abby could have made her comeback to the NCIS franchise via their spinoff. When NCIS: Tony & Ziva was announced, it was revealed that the famed couple would be on the run across Europe. This setup would put them on the defensive, requiring help from allies, particularly familiar ones. Abby, presumed to still be based in the United Kingdom, would have been the perfect candidate to join NCIS: Tony & Ziva.
Aside from the narrative fit, NCIS: Tony & Ziva was Perrette’s simplest path back to the franchise, minimizing the chances of her having to work with Mark Harmon again, which was crucial given their past conflict.
However, with the rest of the NCIS: Tony & Ziva cast now announced, this scenario has become unlikely. The former MCRT members will have an ensemble of experts aiding them. This includes Maximilian Osinski as Boris, a “Russian ex-pat and brilliant computer hacker,” effectively filling the role Abby would have played in Tony & Ziva’s European squad. This new development closes off what was Perrette’s simplest path back to the franchise without the need to work with Harmon again.