In case you've been wondering, Microsoft has no plans to develop a dedicated handheld console similar to Sony's PS Vita or Nintendo's 3DS.
Responding to a question on Twitter, recently promoted Xbox head, Phil Spencer, denied any plans to release such a device. Instead, Spencer believes that it makes more sense to focus on portable gaming through Windows Phone and tablets.
@xrCore I don't think we'll do a dedicated handheld gaming device, rather just focus on WP, tablets, maybe with controller support someday.
— Phil Spencer (@XboxP3) May 5, 2014