Hi mas68,
Thanks for contacting Apple Support Communities!
We understand that you're attempting to connect your MacBook Pro to your Studio Display, but nothing is showing on your Studio Display from the MacBook Pro, correct?
For help to connect your Studio Display and ensure that both devices are compatible together, check out this resource: Set up and use Apple Studio Display
"Check compatibility
Studio Display requires a Mac with a Thunderbolt 3 or Thunderbolt 4 port running macOS 12.3 or later, or an iPad Pro or iPad Air with a USB-C port running iPadOS 15.4 or later.
Compatible Mac and iPad models
Studio Display supports a resolution of 5120 x 2880 on these devices:
Connect your display
Plug the included Thunderbolt cable into the Thunderbolt port on your display and to a Thunderbolt 3, Thunderbolt 4, or USB-C port on your Mac or iPad.
Studio Display doesn't have any buttons and automatically turns on when you plug it into power and connect it to your Mac or iPad."
Let us know if this helps.
Cheers!