Her leaving for Costa Rica (assuming it does go down that way) leaves the door open for Jack to return in the future, which is always a treat for NCIS fans.
It’s been known that Maria Bello would exit NCIS for some time, as Bello’s contract expired in Season 17.
Hopefully, things all go down that way, and the CBS series isn’t looking to burn fans with an unexpected and tragic exit.
She came back in Season 18 partly because the prior season was cut short, and she wanted to ensure Jack got the proper sendoff the character deserved.