Some users have inquired whether the Killer Wireless-AC 1550 is compatible with their desktop mainboards.
Most desktop mainboard M.2 slots are keyed for storage, not for Wi-Fi. You will need to refer to the manufacturer of your specific mainboard, but unless there was a Wi-Fi adapter pre-installed in the mainboard, the M.2 slot is likely keyed for storage. In such cases, no Wi-Fi adapter will work in that slot.
You may be able to use an M.2 to PCIe converter in your desktop. For more information, please see this guide – Installing the Killer 1550 with an M.2 to PCI-E Converter