One of the main new features that came along with Gmail version 5.0 was the ability to manage external email accounts via the app itself. Now it has gone a step further by allowing you to unify all of them in the same inbox, so you don’t have to jump from one account to another to view your unread messages.
This option is compatible with all the providers that already supported IMAP/POP (Outlook/Hotmail, iCloud, Yahoo…) and Exchange, and adding them is quite simple. From the left sidebar you can open a menu alongside your name and associated account and use the integrated wizard. That done, you’ll see a new option called ‘All inboxes’.