From The Information:

In mid-2023, some employees of Apple’s system intelligence and machine learning team, which implements features like computer vision, text analysis and natural language in Apple’s software products, met with Altman and other members of OpenAI. While it’s not clear what they discussed, that same year Apple signed a deal with OpenAI to give Apple employees access to the startup’s conversational AI through application programming interfaces, or APIs, for internal tests.

If they were experimenting with the API a full year ago, we might see more at WWDC than I was expecting.