Slack claims that Microsoft bundling the Microsoft Teams product into Office 365 is an illegal and anticompetitive practice. According to Slack, Microsoft has been "force installing it for millions, blocking its removal, and hiding the true cost to enterprise customers".
"We're confident that we win on the merits of our product, but we can't ignore illegal behaviour that deprives customers of access to the tools and solutions they want," said Slack VP for communications and policy, Jonathan Prince. "Slack threatens Microsoft's hold on business email, the cornerstone of Office, which means Slack threatens Microsoft's lock on enterprise software."