This is a New update from WhatsApp, WhatsApp is now developing a logout feature to enable users logout without deleting their accounts or chat history. As we all know if someone want to logout from WhatsApp the person has to delete his or her account and even delete his or her chat history, and the only to get your chat history back is if they are backed up in your Gmail, but in this new logout feature which WhatsApp is developing it will now enable users to logout of WhatsApp just as will normally logout of Facebook without deleting our accounts or chat history.

https://m.economictimes.com/news/new-updates/whatsapps-new-feature-users-may-soon-be-able-to-logout-without-losing-chats/articleshow/121492611.cms