I call my colleagues using the "Calls" tab in Teams. I am calling their desk phone, which is a land line. Each colleague of mine has their own direct land line number. I use Teams Calls to speak with them. I then wish to share my screen with them, so I find them on the Chat tab, and initiate a screen-share. This immediately places my Teams Call on hold. This is clearly by design, and it is a flaw. We need to be able to share our screens regardless of any other Teams activity. Skype for Business did this flawlessly. I could initiate a phone call to a land line in SFB, open another contact card and initiate a screen share. I'm communicating with the same person, even though the software thinks I'm making two separate connections. Skype for Business did this, Teams does not. Team is useless without this basic functionality. Teams cannot replace Skype for Business until uninhibited screen-sharing is possible.