M.io will help you stay connected and chat with your contacts regardless of what chat platform they use; Slack, SPark, HipChat, and more:
"M.io lets you chat with your contacts on any platform - all from within Microsoft Teams as your central messaging hub. For example, you can chat with your colleagues or external peers that are using Slack all from within Microsoft Teams. It's some heavy duty magic we've been working on and we're excited to start sharing with the community."
If you are interested in becoming a beta tester for M.io, you can sign up using your email. It will be interesting to see how M.io works within Microsoft Teams, but it looks like it'll be an even better way to stay connected and collaborate. Stay tuned for more information on this feature in an upcoming Microsoft Teams update!