It seems WhatsApp is working to bring a new app for Windows 10 PC version. The Beta app for WhatsApp for desktop has appeared in the Windows store.
Currently one can download the desktop app from WhatsApp site which is nothing but a WhatsApp web wrapper. This new app may bring more functionality to the desktop app.
As one can expect from this private Beta listing it is not available to download for everyone. Only if you are a private Beta tester you would be able to download and install it.
As per the details provided with the listing the Beta app is only compatible with x64 architecture.