NVME PCIe SSD to SATA adapter exist? MB Pro 2015 have NVME PCIe SSD which are super fast. I was thinking to replace mine with a bigger capacity one. And then use the old one in a Windows laptop, if that's possible. Since my Windows laptop have SATA SSD I need an adapter, so NVME PCIe SSD to SATA adapter exist?
You'd need SATA at one end and Apple's own "12+16-pin" PCIe connection, which is different from the M2 industry standard connectors used on SSD blades in other PCs. 

You can do your own searching, but I suspect such things are hard to find. You would have more luck with adaptors that connect an Apple SSD blade to a USB port as an external drive, but these can be expensive.