

Microsoft is launching a major new ad campaign for Teams, its work-communication app, which has been duking it out with Slack for dominance in the workplace.

A new global ad campaign from Microsoft will aim to sell "The Power of Teams," juxtaposing old-school conference room meetings, complete with packets of printed-out charts and spilled coffee as phones are passed, versus what the company pitches as a new way of working. The company worked with its agency, Interpublic's McCann, on the campaign. It will launch in the U.S. on Sunday during the NFL playoffs and will include TV ads, podcasts, digital and out-of-home placements. The campaign will launch in February in the U.K., France and Germany.

Slack shares dropped after CNBC reported news of the Microsoft ad campaign, and are now down more than 2% on the day.

Teams, which launched in 2016, is a collaboration tool that offers chat, meetings, calling and file collaboration. Microsoft said in November that it had more than 20 million daily active users, a 54% increase from its prior announcement about usage and apparently more than Slack, which said in October it had 12 million daily active users. That raised some questions from analysts (and Slack) about what Microsoft considers an active user, but the tech giant argued its metrics were fair, saying that just because Teams is installed on a PC and automatically opens on start-up doesn't mean the person gets counted as a user.