AWS uses Slack Internally.
[1] https://www.theverge.com/2020/6/4/21280829/slack-amazon-aws-...
Kind of sad as video is a extra paid feature!. It is very limited in functionality, no screen share or view on mobile, no easy way to do audio/phone bridge.
The connections or bad that my org disabled audio/video calling on slack and encourage users to use Teams only.
[1] https://www.theverge.com/2020/6/4/21280829/slack-amazon-aws-...