I’m excited to announce that this feature is in internal testing, and should be coming soon! Thanks!~ AlexChristian commented
Yes, status change alerts are very helpful to manage interaction and expectations. Have used those always in Skype (Classic), Skype for Business and other IM tools.
We acknowledge the demand for this capability and are exploring the best possible solutions to enable this.
usability with multiple parallel chats is much better in Skype for Business