Mio does not create any additional end user licensing requirements.
There are free versions available for all of the chat applications supported by Mio, including:
Microsoft Teams (included with Office 365)
Cisco Webex Teams
Our partnerships with Slack, Microsoft, and Cisco means that we can offer you state-of-the-art chat application federation, without extra costs.
If you're using auto-sync in Slack, your Webex Teams and Microsoft Teams users won't contribute to the Slack membership count in channels or anywhere else. Mio automatically provisions bots for those users in Slack, so they'll show up under Apps.
Syncing your favorite chat apps with Mio doesn't cost anything extra on top of your current costs for chat user accounts—even if you're using the free tiers.