Apple is expected to show OS X 10.9 at WWDC. The latest version of the venerable Mac operating system will further Apple's efforts to migrate iOS features to OS X. Last year's OS X 10.8 Mountain Lion update, for instance, brought over a bunch of iOS tools, including Dictation, Notification Center and iCloud document syncing.
Rumors suggest OS X 10.9 will add Siri and Maps too. The addition of iOS's poorly received (but improving) mapping app would be an intriguing choice, particularly when Google Maps or Bing Maps inside a browser window work quite well on a Mac. Apple's main motivation may be to keep Google and Microsoft at bay.