When Summer and Kyle flew off to Italy in 2021, it wasn't the first time that Hunter King departed "The Young and the Restless." King began playing a teenage Summer in 2012 but left the soap in 2016 to focus on her primetime role as Clementine Hughes in the series "Life In Pieces" (via IMDb).
When King returned to "The Young and the Restless" in 2018, Summer had become a bit manipulative and tried to seduce her mother's boyfriend, Billy Abbott (Jason Thompson), something Phyllis Summers (then played by Gina Tognoni) didn't appreciate.
She then set her sights on her ex-fiance, Kyle Abbott, and didn't care that he was dating Lola Rosales (Sasha Calle). She wanted Kyle for herself and was determined to get him. Although Kyle married Summer, he quickly dumped her for Lola; he then dumped Lola when he realized he always wanted Summer. After a series of mishaps, Kyle and Summer took off to Italy for a new life in 2021 and married off-screen (via Soaps In Depth).