IIRC sometime last year teams passed slack for daily & weekly users pretty comprehensively. Office 365 is heading close to 200m users. Slack and Teams use is

IIRC sometime last year teams passed slack for daily & weekly users pretty comprehensively. Office 365 is heading close to 200m users. Slack and Teams use is both in the low 10s, but teams is growing fast into that 200m since it is bundled and interacts with the other parts.