Chosen Solution

I was wondering if my MacBook Pro has a PCI or PCI-E Slot anywhere in the Laptop. Because I’ve been searching for hours and I’ve got no answer. Any reply would be highly appreciated!

Laptops are not desktops! So extension adapters are just not possible. Besides theres not room ;-} The newer MacBook Pro Touch and Function key models do have a fast enough external I/O (Thunderbolt 3) that you can connect an external chassis to house PCIe adapters like a graphics card.