This is my reference for wifi and Bluetooth upgrade on my Mac Pro 5,1. I have already upgraded my system to Catalina (because the new OS doesn't recognize wifi and Bluetooth of the old model), so I use this solution as the standard upgrade. For your reference.
Classic Mac Pro (5,1): Upgrade Wi-Fi to 802.11ac and Bluetooth to 4.0
It is worth noting that you need to buy a wire called U.Fl Ipx (sorry I am not familiar with that field, but I know that wire can connect them to each other), you can see the picture I attached.
My purchase list is
1. BCM94360CD to mini PCI-E adapter card (with cable)
2. BCM94360CD chip (no driver required in macOS)
3. U.Fl Ipx cable
With these things, you can complete this upgrade. The attached link has detailed instructions (thanks to the kind gentleman) and there is no need to remove the motherboard during the process, just a deft !