Best answer: Yes, you’ll need an Xbox Live account to play Halo: MCC on PC. One can be created free of charge on Xbox’s website.
Get the MCC: Halo: The Master Chief Collection ($30 at Amazon)
What’s Xbox Live and how does it work with Halo: MCC?
Xbox Live is Microsoft’s online service that provides Xbox and Windows 10 players with a place to buy and play games, download apps, and more, all for free. If you want to play games online with other people on your Xbox One, then you’ll need to traditionally purchase an Xbox Live Gold subscription for your Xbox Live account. However, this is not the case for Xbox Live games released on other platforms and services — you can play, for example, on your PC for free.
On PC, the Halo: Master Chief Collection (Halo: MCC) is launching on the Microsoft Store as well as Steam. As per the information on the Steam page for the game, it will require an Xbox Live account. Thankfully, players will not need Xbox Live Gold based on the above rule. All you’ll have to do is connect a free Xbox Live account to your game, and you’ll be good to go.