Both Sophia Bush and Jesse Lee Soffer wanted to leave Chicago PD, but the writers only got one of their exits right. It can be hard to create a fitting ending for a character when the actor asks to leave a show. Sometimes writers and showrunners choose to kill off the character for an emotional episode, but that doesn’t always go over well with fans. That can be an easier way to end a character’s story. Unfortunately, creating a reason for the character to move away can prove more difficult.

https://screenrant.com/lindsays-exit-was-more-realistic-than-halsteads-on-chicago-pd/