Microsoft is partnering with Transatel to provide cellular data services for Windows 10 PCs and tablets, but not phones. It will launch in France, the United Kingdom, and the United States, but could be rolled out to other regions over time. This will not be a contract service. Everything will be pre-paid, with short-term plans (think “XGB for the next 30 days for Y upfront”) available for a discount before a trip or something.
Despite the source being a Microsoft corporate VP, speaking on the record, it has not been officially announced by the company yet. Details, like when it will be available, have not been released.