What's better than a fan favorite returning? The fact that he will be free for a limited time.
Until the Zenny shop (which players will use to purchase skins, titles, and additional characters for cash or earned currency) is released, Guile will be free. After the shop launches, he will be available for purchase with real world money, or the currency earned in the game. He comes with his own set of Trials and Character Story.
A new stage is also being added, and it brings us back to the classic Air Force Base. Season pass owners get it for free, and it will be available in the Zenny shop for 70,000 FM (fight money) when the shop is eventually launched.
Guile will be coming in the April update.
(Source: Capcom Unity Blog)