Facebook might put chat option back on its main social app by merging messenger app and main social facebook app together. The feature is currently in testing and was spotted by app researcher Jane Manchun Wong. This means you could use a single app to access both the social media platform and elements of the messaging service.
Back in 2011 Messenger was released a standalone app and in 2014 Facebook removed chat functionality from the social app to force people to download Messenger app.
In her tweet, she also said that this Chats section only contains a limited selection of Messenger’s features. Although you can use it to send and receive messages, you’ll still need to open the standalone Messenger app to make calls, send photos, or send message reactions.
Although she believes that the Messenger app will be kept around to serve a different audience than the main Facebook app.