Black Screen/No screen activity

Sounds like a hardware problem. Make an appointment at the Apple Genius Bar for service after the stores re-open. If you need to find an Apple Store - Find a Store - Apple. Also, see How to find your nearest Apple Authorized Service Provider (AASP) or Distributor (AAD). You may also get Apple authorized service at a local Best Buy or contact Apple Support for more options.

Contacting Apple Customer and Support Service

1. Apple Store Customer Service at 1-800-676-2775 or visit online Help for more information.
2. To arrange a return, repair, or replacement: Returns  &  Refunds  -  Apple  Store  (U.S.,) and Mac Repair.
3. If you just purchased the product, then you get 90 days of free telephone support from the date of purchase of your Apple product.
4. Primary support help at Contact Support.
5. To contact product and tech support: Contacting Apple for support and service including international calling numbers.
6. Product  Service  and  Repair  information.
7. Apple  Service  Programs.

I had the same issue recently with my MacBook Air. Took it to the service centre, where I got to know about the hefty amount I need to pay because my warranty had expired in June. Anyway, he told me that he has seen many cases like this and asked me to register my complaint with Apple. I'm hoping they start a repair program for MacBook Air retina display, as there is an ongoing MacBook Pro display repair program with people facing the same issue

Check if you get output on external monitor. Should help to isolate if there is issue with built in display.