Inbox By Gmail New UI:
The new search UI separates the search in three categories. Contacts, Businesses, and Refinements. These three categories I found in Inbox app's new search UI.
Contacts and Businessses category will show you people or list of companies which you contact regularly. And Refinements have the all other options.
Here what Android Police has mentioned on their website for this update: It's possible this is the first indication of the "Assistant" feature Cody unearthed in a recent teardown, but we can't really be sure.
Click below to Download the APK file to Get this New Inbox App UI
Note: I have installed the update on my Xiaomi Mi 5. As the new layout is on server-side. So, you might get the new layout little late.