Jennifer Morrison played Dr. Allison Cameron in the medical procedural House, a character whose compassionate, idealistic nature often clashes with Dr. Gregory House’s (Hugh Laurie) abrasive, cynical outlook. Given her significance, fans were surprised when Morrison was written out of the show in season 6, as she was the first of the original cast of House to leave the series. Cameron had already taken on a more background role when producers decided to shake up House‘s formula in season 4 by breaking up House’s team, leading to some of House‘s best episodes.

https://screenrant.com/why-jennifer-morrison-cameron-left-house-season-6-explained/