Thankfully, Google will keep Inbox plugged in through March 2019, so you at least have a healthy amount of time to get reacquainted with Gmail (Android, iOS) - which has been busily incorporating and expanding upon a number of Inbox features, such as smart replies.
The launch of the new Gmail in April was surely a sign that Inbox, Google's productivity-focused mail app, would soon meet its demise.
Inbox began as an email experiment almost four years ago for Google.
One Inbox by Gmail feature that still hasn't made its way over to the standard Gmail service is the email bundling. Fortunately, because Inbox requires a Gmail account to use, all the messages in their Inbox account are also still on Gmail. As a result, we're planning to focus exclusively on Gmail and say goodbye to Inbox by Gmail at the end of March 2019. Like you can use Stars, custom labels, or use Gmail search if you used Pins in Inbox. Things that started out in the app like Smart Reply and viewing attachments right within the main screen have been added to Gmail, many coming in the last big redesign. There's a transition guide that includes a list of Inbox features that have arrived in Gmail, as well as alternative features that offer similar functionality. At the time when it launched Gmail lacked numerous features it has today. At that time, any Gmail addresses that were tied to Inbox will revert to the standard Gmail experience, and the mobile app will stop working.
Now You: Are you affected by the termination of Google Inbox? Having about six months of warning will give Inbox fans a chance to get their personal workflow going in Gmail, but it'll probably never be the same. Gmail, by comparison, is very busy, even the new version.
When I reviewed Inbox back in 2014 I quickly realized that the service was not something that I wanted to use.