Huawei has released an app called HarmonyOS Interconnect in China, and it lets an Apple Watch pair with some of Huawei's phones. The phone has to run HarmonyOS 7.0 or newer (Huawei's own phone software), and The Mac Observer reported that only a few flagships qualify for now: the Pura X View, the Mate 90 series and the folding Mate XT 2. The app goes on both the phone and the watch. The watch gets the app from the App Store, so you still need an iPhone to set it up the first time.
Once the two are paired over Bluetooth, the watch shows incoming texts, app notifications and calls. You can't answer a call from your wrist. None of your health or fitness data reaches the Huawei phone, so your steps and workouts stay in Apple Health on an iPhone. If you've moved from an iPhone to one of those Huawei phones, the watch still handles your messages, but it stops being your fitness tracker.