If we receive external MS teams invitation and it doesn’t have CVI details, is there a way to join from Cisco VC kits? (workaround or leverage our CVI)?
If you enable join via WebRTC you would be able to. CVI is tied to the host so if they don't have it you can't leverage it. Below is the link explaining how setup and use WebRTC for Teams.
SO it means it will work only to those webex VCs which supports WebRTC, and initiator has CVI enabled.
What about old vc like Sx80, 20 etc. There is no way to use that.
For WebRTC the initiator does not need to have CVI. These are two different options for how to join the meeting. With WebRTC the device needs to have support for a web client and be configured to enable the use of a web client on the video device itself. The older devices do not have support for this, so they would not have the possibility to join via WebRTC.
On older devices you would not have the ability to join with WebRTC. If you are trying to join a CVI as long as the device supports SIP dialing it can join the CVI meeting.
As Roger mentions CVI and WebRTC are different options to join a MS Teams meeting.