Saint John, head of Global Consumer Marketing for Apple Music, was one of Fortune’s 40 Under 40 last year after making a splash with a presentation showcasing Apple Music at its World Wide Developers Conference. She also spoke at Fortune’s Most Powerful Women: Next Gen summit.

Apple has not yet responded to a Fortune inquiry about the departure. Apple declined to comment on the original Axios report.

Saint John’s departure would be a significant blow to Apple’s battle for mindshare among music services. Prior to moving to Apple, Saint John was a music-industry rainmaker who helped engineer Beyonce’s 2013 Super Bowl appearance and promotional deal with PepsiCo, at which Saint John served as head of music and entertainment marketing. After joining Apple as part of its 2014 acquisition of Beats, Saint John helped bring together Mary J. Blige and Empire star Taraji P. Henson for a widely discussed commercial series.

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Apple Music made significant strides against competitors including Spotify and Pandora during Saint John’s tenure at the company. In December 2016 Apple reported 20 million paying subscribers, a substantial increase from the 9 million it started the year with though still well behind Spotify. One marketing company claims Apple’s total users went on to more than double this year thanks to a free trial promotion, though that analysis is disputed.

The departure of Saint John, who was born in Ghana, would also have implications for Apple’s efforts toward diversity in staffing. Like the rest of the technology industry, Apple has received its fair share of scrutiny for the perception that it’s dominated by white men. (For example, of the 18 people listed and photographed on the Leadership page of Apple’s website, 15 are men.) Though the company’s overall racial inclusiveness is not too shabby compared to its peers, only 32% of all Apple employees were women as of mid-2016.