Huawei has been put on the United State's Entity List, meaning that it cannot trade with any US companies. This is kinda old news now and a potentially severe blow for the China-based company. Now, the company has been dealt another blow. Facebook bans its app on Huawei phones. The App cannot be pre-installed on any Huawei phone that has not left their factories. That includes the current models or otherwise.
Google's has a temporary licence, meaning they can still trade with Huawei for now. The licence is effective from the 20th May all the way through to 19th August (a total of 90 days.) Facebook has found a different way to deal with the US ban than Google.
Now that Facebook bans its app on Huawei phones and won't allow their app to be pre-installed - Huawei phone users will still be allowed to download apps like WhatsApp and Instagram. Facebook will not be accessible via the Google Play Store.
As we can probably see, Huawei is going to struggle quite a bit unless Trump decides to change his mind any time soon.