Ross will be replaced by Pierre Hintze as the new studio lead.
Bonnie Ross

Bonnie Ross announced her retirement today, citing "a family medical issue" as the main reason for her departure. Ross has been the lead at 343 Industries and the Halo franchise for the past 15 years, having worked at Microsoft and Xbox for 28 years.

In her Twitter post, Ross says she originally intended to leave following the Winter update's release for Halo Infinite. She also says that she is "incredibly proud of the work everyone at 343 Industries has done with Halo Infinite, the Master Chief Collection, the Halo television series, and so much more." Ross continues to say, "It has been an honor to serve alongside the team for the last 15 years and to be a part of the universe that I love."

Additional reporting by Windows Central says that Microsoft plans to break up the leadership roles for 343 Industries and Halo into multiple roles. Pierre Hintze will succeed Ross as the head of 343 Industries while Bryan Koski will become the general manager of the Halo franchise. Elizabeth Van Wyck will take over the business and operations side of things.

Ross was part of 343 Industries from its start in 2007. She oversaw development on Halo 4, Halo 5: Guardians, Halo Infinite, and Master Chief Collection. Prior to her work at 343 Industries, she helped work on franchises like Gears of War, Alan Wake, and some third-party publishing deals like Mass Effect.