In his Season 21 appearance, Barba is video-chatting in from Iowa, where he’s “trying to blend in” with a beard. We never find out why he’s there (but the episode coincided with the week of the Iowa Primary) because he’s more keen to catch up with Benson and wish her a happy birthday before anyone else.
“You know it’s been rough. A lot of loss lately,” she responds, alluding to the rough season she’s had so far, during which both her brother Simon and her ex Ed Tucker have passed away.
Show runner Warren Leight had promised to try and make a Barba appearance happen on this season “sooner rather than later,” and expanded on his plan to bring actor Raúl, who he calls his “partner in crime” back this landmark season, which he’s envisioning as a three-act story.
Source : https://www.distractify.com/p/is-barba-coming-back-to-svu