At Twinspires, we live and breathe collaboration, with our primary artery these days being Slack. If it doesn't happen in Slack, maybe it's in Outlook. Teams is rapidly becoming a fierce competitor to Outlook... the assumption is if it's not in a chat within Slack or Teams, it's probably an email sitting in Outlook (as one of my co-workers likes to say, "I can't believe people still use email!", lol).
We use automation to notify people when issues have been moved to a particular state. For example, we have automation in place to notify our Product Owner that an issue has been marked Done and is ready to be reviewed for acceptance. We have other teams who have similar automations to send emails when various issues have moved to a particular state. And - of course - we have Confluence pages we're watching with interest... and we receive either weekly summaries, daily summaries, or up-to-date alerts when those pages are updated. As we leverage our Confluence dashboards to help manage our teams, we have executives who watch certain pages for updates, which alert them to updates to our metrics; this way, they become aware of updates which may pique their interests.
To date, we've not attempted anything per se with Teams; it's still further down the stack than our focus at the moment.
As we strive to deepen our integrations between Jira and Confluence with Slack, Outlook, and Teams, we are constantly on the lookout for the next best thing. What are you leveraging in your domains?