According to Bloomberg's Mark Gurman, Apple is laying off roughly 100 employees in its Digital Services group, with the main group affected by the cuts being the team that works on the Apple Books app and its associated store.
Apple Books, introduced by then-CEO Steve Jobs in 2010 to coincide with the launch of the iPad, never became the “Kindle killer” that Apple hoped it would be. The cuts indicate that Apple Books will no longer be a focus of Apple investment. The Apple News team, along with other services teams, will be affected by the layoffs.
In Apple's most recent quarterly earnings, services accounted for 28% of revenue, but the majority of that revenue likely came from in-app purchases and App Store subscriptions. It's unclear whether Apple can maintain its dominance in mobile app distribution amid a shifting regulatory environment.