Today is the second day of Microsoft's Build 2018 conference, and the keynote is being held by Joe Belfiore. Focused on Microsoft 365, Belfiore announced a number of features that are coming to Windows 10, such as the new Your Phone app that brings additional continuity between your phone and your PC. But there are also new features coming to Timeline and Sets, which Belfiore said will be in the next Windows 10 Insider Preview build.
One thing that's new is that Cortana will offer suggestions for 'Pick up where you left off'. This is a new part of the UI, rather than just the pop-up messages that we've seen before.
And then there are the new Sets features. For one thing, browser tabs will now be included when you hit Alt-Tab. It's unclear if you'll be able to turn this off, since it might get a bit cluttered with a bunch of tabs open.
What's more exciting is that Sets are coming to Timeline. In other words, you'll be able to pull up entire Sets from weeks ago and pick up where you left off on the entire thing.
Unfortunately, Belfiore also specifically said that Sets aren't guaranteed to ship in Windows 10 Redstone 5, which is due out this fall. You might recall that last year, he announced that Timeline was coming in the Fall Creators Update (version 1709), but it didn't ship until this spring in the April 2018 Update (version 1803). Microsoft wasn't going to make that mistake, promising not to ship Sets to production until it's "great".