Depending on the phone you use, the Android recent apps menu is usually different. For MIUI, the apps are arranged horizontally and can be shrunk to just icons or expanded. For OxygenOS and stock Android, the recent apps are arranged in a vertical card system. When Android P launches, the recent apps menu will be redesigned.
According to 9to5Google, Android P will switch to a horizontal arrangement for the recent apps menu. The apps will still be arranged behind each other and not side-by-side like in MIUI.
It will work in a similar fashion as the current vertical arrangement. Swipe to the left to select the app you want to switch to and a swipe upwards should close an app. However, that isn’t the only change coming.
The recent apps button may also be removed, leaving just the home button which is now pill-shaped and the back button. To access the recent apps menu, one will need to swipe the home button up. When at the home screen, the only visible button will be the pill-shaped home/recent apps button. The back button is said to disappear later.
The removal of the recent apps button may be a gradual move to a total gesture-based navigation for Android. This makes sense since most manufacturers are releasing devices with thinner bezels and on-screen buttons.
Nevertheless, there is a chance this may still not make it to the final release.