Thanks to the addition of add-ons, you no longer need to constantly switch between applications and can use third-party apps directly from Gmail. In a blog post, Google explains what is possible with the added add-ons.
The first parties whose add-ons have been added to Gmail are all business-oriented: Asana, RingCentral, Trello, DialPad, Smartsheet, Streak, Intuit QuickBooks, and Wrike.
Google Gmail add-ons
Add-ons can be installed from the marketplace of Google. The company also announces that developers can relatively easily create add-ons for their application to integrate them into Gmail. It is not known whether and which parties will come out with their own add-on in the foreseeable future.