On the Samsung device, we can grant or revoke permission for apps to create a picture-in-picture window and let other apps show it, so for example videos/movies can still be viewed in a small window when the app is closed.

Android 10 (One UI 2.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Apps
Step 3:  Open the  menu
Step 4:  Tap on  Special access
Step 5:  Tap on  Picture-in-picture
Step 6:  Tap on desired  App
Step 7:  Enable or disable  Allow permission
  1. Open the Settings
  2. Tap on Apps
  3. Open the menu
  4. Tap on Special access
  5. Tap on Picture-in-picture
  6. Tap on desired App
  7. Enable or disable Allow permission

Samsung Instructions