Apple's WWDC 2020 event may not showcase all the new hardware launches we've been expecting so far. Instead, Apple is expected to focus on new software updates and announce the existence of ARM-based Macs so as to get developers up to speed. Apple analyst Ming-Chi Kuo expects Apple to fully transition to ARM in 2021 starting from the ARM-powered 13-inch MacBook Pro and redesigned iMac.
https://www.notebookcheck.net/WWDC-2020-may-not-see-new-hardware-reveals-full-transition-to-ARM-expected-starting-from-13-inch-MacBook-Pro-and-redesigned-iMac-in-late-2020-or-early-2021.477089.0.html