It has just been announced that Skype for Business Online (SfBO) will be retired by July 31 2021.
Starting September 2019, new Office 365 tenant will be on-boarded directly to Microsoft Teams.
This announcement has no impact for Skype (consumer) or Skype for Business On-Premises.
You can get the complete announcement here https://techcommunity.microsoft.com/t5/Microsoft-Teams-Blog/Skype-for-Business-Online-to-Be-Retired-in-2021/ba-p/777833?fbclid=IwAR0TvAbcRBZAnGm5fxpaEoYsaPvHfHyH1VyEMEE35AQ5tqAIwDH1elBiodc