While Teams is replacing Skype for Business as the default chat client in Office 365, there’s still room for both apps to exist, as Teams has more of a focus on workplace group chat, while Skype is more about audio and visual communications. Also, Microsoft is releasing Skype for Business Server 2019, ensuring the app’s future for years to come, especially in enterprises that specifically want an on-premises install of the application. Additionally, the consumer version of the app will continue to use the Skype branding. Finally, some users believe that the communications features in Teams doesn’t measure up to the functionality in Skype for Business. For all of these reasons, it makes sense for the applications to say separate because many will still want to use Skype going forward.