Slack has been using data from your chats to train its machine learning models The only way to opt out is by asking your company’s workspace owner to send Slack an email.

How to opt your company out of Slack's AI training The bad news is that you, as an individual user, cannot opt out of Slack using your conversation history to train its large language model.

Slack Trains Some of Its AI-Powered Features on User Messages, Files Slack feeds user content, messages, and uploads to its machine learning models. All users are opted-in by default.