A chief marketing officer - or CMO for short - is a very important person in charge of making sure lots of people know about a product or service.
When a company has something they want people to buy or use, the CMO is the person who figures out how to make that happen. They come up with ideas and plans for how to tell people about the product or service and get them interested in it.
They might work with other people like designers, writers, and advertisers to create ads, commercials, and social media posts that make people want to try the product or service.
The CMO also helps figure out how much money the company should spend on advertising and where the ads should be placed so that the most people see them.
In short, the CMO is responsible for making sure everyone knows about a company's product or service, and that people want to buy it.