I’ve heard concern, as I do nearly every year, that the omission of any Mac news at the 2016.03.21 Apple Event spells doom for OS X as a platform.
To recap, at said event Apple released the 9.7" iPad Pro, along with the iPhone LE; two additions to its iOS product line. In addition, Apple released CareKit, a developer framework for healthcare-related iOS apps.
Two new products and a developer framework, two full months before the Worldwide Developer Conference.
Whatever Apple’s got planned for WWDC, it’s got to top that for Apple to get them out of the way. I don’t know that a full refresh of the Mac lineup is coming, but it certainly isn’t unreasonable considering all Macs today run on Broadwell or earlier processors. Given Apple’s trend over the past few years, I’d be very surprised if a new Mac OS wasn’t released. Either way, the lack of Macs in mentioned in March means nothing for announcements to come in June.