What Is Cloud.microsoft?

As Teams (well teams-for-linux anyway) has now updated with

> Teams has a new URL: teams.cloud.microsoft. Same app, better security.

it's now in your face. Personally I find these custom domains raise my scam concerns, but I suspect that's just a symptom of age and cynicism.

I do wonder how long it will be before sites which aren't on an approved top-level-domain (.google, .microsoft) are treated as risky and perhaps even blocked by organisations and browsers