Five-Zero is going to start again later this month.

I don't want to read any spoilers about it, so I'm trying to ignore most media about the show. I did see something about, "The team says goodbye to one of their own", so presumably some regular from the show is leaving.

Without knowing anything further (and please don't tell me if you know), my guess is Adam. They kind of ran that character into the ground, and there's really not much left to do with him. Also, actor Ian Anthony Dale has had roles in other series during the 2010s, so it's conceivable that he could simply be moving to another show (perhaps one on CBS).

I could also see Grover leaving the show, but I think Chi McBride is happy living in Hawaii and collecting a nice paycheck at this point in his life, so I don't think he's going anywhere, nor do I think the show wants to drop his fairly stable character.

It would be annoying if Tani or Junior left, since they've been building up this romance between them which hasn't yet quite happened, and it would frustrate me to see that was all for naught. Both of these characters are also pretty good, which made the departure of Chin and Kono much less noticeable.