As we always remember here on the site, the Worldwide Developers Conference (WWDC) an event for developers and very focused on software. However, it is not unusual to see in the opening keynote of the event either hardware release.
A few days ago it was said that we will see the arrival of the rumored loudspeaker for Siri and perhaps even a new 10.5 ″ iPad. Today the Bloomberg said Apple also seize the occasion to update its lines of MacBooks.
Yes, in the plural: vehicle sources cited an upgrade in MacBooks Pro with processors Kaby lake from Intel, new 12 ″ MacBooks with faster chips and maybe even a small update on 13 ″ MacBook Air which, they say, still sells very well. The three would come as a kind of "answer" to Microsoft's recently announced and well-received Surface Laptop.
In the case of MacBooks Pro, there is still the rumor about the adoption of Apple's own chip for better power management. But the Bloomberg I could not say if we will see this news coming in the next month.
Externally, no visual changes are expected on any of the MacBooks.