M.2 slots come with different keys for different purposes. key B is used for WWAN and mostly SATA SSDs (although some slower NVMe drives ship with key B+M , the

M.2 slots come with different keys for different purposes. key B is used for WWAN and mostly SATA SSDs (although some slower NVMe drives ship with key B+M , the plus sign means it works in both slots). key M is used for x4 NVMe SSDs. And key E is used for wifi. And this card here.