The ChatGPT app is getting ads, but Google's Gemini app isn't for now

OpenAI said it would not share advertising profiles with other companies. — Reuters

SAN FRANCISCO: OpenAI has announced plans to introduce ads to ChatGPT, with tests in the United States set to start "in the coming weeks" – well ahead of Google, which says it does not have plans to show ads in its Gemini app.

Your chat history inside ChatGPT will be used to create ads that target your preferences, but OpenAI notes that you can turn off "personalisation" if you want.