Tbf, it works but not like it used to in MIUI 11, the swipe gesture that activates pip in apps isn't working, i noted that it only works if for example I'm watching a video on YouTube and get a notification, if I tap the notification then the pip function starts, opening the app of the notification and the little window player, I also noticed something funny, that if I search picture in picture in settings app, it appears as a feature but if I tap on it it becomes a black screen like its not available (Screenshots in Portuguese)