Ability to restrict user access to a bot or grant access based on Authentication
Ability to restrict user access to a bot. - Authentication to use bots and / or ability to create private bots (I.e. Bot in teams only for a company’s internal use).
Bot Service introduced Bot Authentication capabilities at Build 2018. You can read more here: https://docs.microsoft.com/en-us/azure/bot-service/bot-builder-tutorial-authentication?view=azure-bot-service-3.0