My iPad Pro screen goes black but I can still hear the sound

When does this occur? Does the screen go black when a specific app is opened?

If it's all the time, consider speaking to Apple Support regarding your repair options. (Contact - Official Apple Support). If you didn't damage the iPad yourself, the cost of the repair may be covered by AppleCare.

If your iPad was purchased directly from Apple within the last 14-days, in most countries Apple will allow you to unconditionally return your iPad for exchange or refund. If this applies to you - and you are experiencing difficulties - you would be well advised to make use of this opportunity while it remains available to you.

Otherwise, you might be best advised to seek assistance directly from from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively, if you have access to another Apple device, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed, the App can be downloaded from the App Store:

https://apps.apple.com/app/apple-support/id1130498044

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad:

Genius Bar Reservation and Apple Support Options - Apple