App ads have been in the App Store before. When downloading any of them in the App Store, you may have noticed ads that rose above the rest with an ad tag. Now Apple has made ads more like those used on Facebook | Instagram by allowing developers to test different layouts with up to 35 features showcased in individual ads.
Each of the ads can be customized in different ways for search results and keywords directly in the App Store app. Thus, users who enter different keywords into the search may see different ads showing the distinctive features of the same application.
To use this feature, you need to sign up for the paid Apple Search Ads platform.
A source: 9to5mac