Although one actor is leaving The Rookie ahead of season 7, the ABC series gains two more, who join the veteran cast during the premiere. The police procedural show, created by Alexi Hawley, follows the personal and work lives of the law enforcement officers who work at the Mid-Wilshire Patrol Division in Los Angeles. However, as its name implies, The Rookie mostly revolves around first-year cops. As time goes on, though, newbies filter in and out of the station (or are promoted and remain a part of the list of characters).

https://screenrant.com/the-rookie-season-7-cast-character-guide/