For those concerned with cross-platform play on Windows 10 meaning that they would have to pay for Xbox LIVE on their PC, you won’t.
As cleared up by Larry Hyrb, AKA “Major Nelson”, playing Xbox LIVE enabled games when in cross-play with your Xbox One friends on Windows 10 will not require a subscription for your PC. Allowing for traditionally Xbox-only messaging and the highly touted Xbox LIVE cross-play, Windows 10 titles may be cross-buy compatible if the developer allows it and will also feature DirectX 12 for significant boosts in graphical power. Here is the direct quote from Larry on the topic of LIVE for Windows 10:
@haydencd Not charging. Xbox Live Gold will not be required for online multiplayer gaming using our service on Windows 10 PCs and Phones
— Larry Hryb (@majornelson) March 5, 2015
Windows 10 will be available for free to some existing Windows operating system owners. If you’re interested, check out the full details of the freebie announcement here.