Inbox by gmail was launched back in 2015. It is packed with various exclusive features in it like Undo Send, Signatures, and Swipe to Delete. All these features are not present in gmail app at that time. But, Now Google announces that Inbox will be shut down by the end of 2019.
The reason behind the shut down is the recent updates to Gmail App. Gmail get the features like Smart Reply, Nudges and high-priority notifications recently. So there is no point to continue with two email apps by the Google with almost same features. That why they decide to shut down by the end of March 2019. So they are focusing more on Gmail.
After the Gmail Makeover Google says about inbox by gmail
“With respect to the upcoming Gmail announcement, there are no changes to Inbox by Gmail. It remains a great product for users with specific workflows and one in which we test innovative features for email.”
Users who are using inbox for years will be very upset. It will be hard to change But Google has made a guide how you can transit from inbox to gmail.