It appears that Microsoft was contemplating the release of a Windows Phone 8 device named the "Microsoft Surface Phone" back in 2013. This move was seen as a step in the direction of Microsoft manufacturing its own branded mobile devices, similar to the way it had ventured into manufacturing its Surface tablets.
The decision to create a Microsoft-branded phone suggests a strategic shift towards more control over the hardware and software integration, a philosophy that has been successful for companies like Apple. This move could also potentially raise the bar for other Windows Phone manufacturers, encouraging them to innovate and improve their offerings.
While the specific details and outcome of this plan are not mentioned in the source provided, it's interesting to see how Microsoft aimed to tighten its hold on the mobile device market with a dedicated Windows Phone device.