Siri
As expected, Siri is coming to the Mac. Siri will be able to search for files, and refine those searches by indicate specific apps and people related to the files.
Universal Clipboard
Copy it on your iPhone, paste it on your Mac. And vice versa.
Tabs
Every app, including third-party apps, will be able to have multiple tabs. That means Map tabs, Twitter tabs, any kind of tabs you can think of. (And there’s no optimization needed by the third-party developers.)
Auto Unlock
iPhones will gain the ability to unlock your Mac when you get close to it—this serves as a double-edged sword for security. Since you don’t have to regularly enter your password, you could choose one that’s more complex, but if your phone and laptop are both stolen, the thief has a key.
Apple Pay online
Apple is expanding its digital payment service to the internet, and you’ll be able to authenticate payments by either using Touch ID or tapping a prompt on you Apple Watch.
Smart file storage
Your Mac will be able to find redundant files and other space-wasting apps, and automatically clean them up.
Picture-in-picture
Videos, like from YouTube or Vimeo will now be tiny movable little boxes.
macOS Sierra will be available in a public beta in July, and available generally in the fall.
Follow all of our WWDC 2016 coverage here.