During a Game Developers Conference panel today, Xbox boss Phil Spencer praised Steam and what the company has done for PC gaming over the past ten years.

"They've been the backbone of PC gaming for the last decade," Spencer said. "As a Windows company, I appreciate what they've done."

Steam has focused on PC gaming more, in a lot of ways, than Microsoft has, Spencer said.

Also during the panel, Spencer said PC gamers can expect "more focus" from Microsoft in the PC gaming space in the time ahead. Spencer stressed that Microsoft doesn't plan to compete directly with Valve, but said "it's important to invest in [PC gaming] in a real way."

Finally, he said PC gamers will see "tier-1" initiatives for PC gaming from Microsoft beginning this summer, though he did not say more.

Earlier this week, Microsoft announced Direct X12, the latest version of the graphics API that promises major improvements for Xbox One and PC developers.

Valve is, of course, soon to become a competitor to Microsoft in the home console space with its line of Steam Machines. Spencer isn't worried about the competition though. Steam Machines "make sense" for Valve, Spencer said, because the company already has an established storefront and 65 million users--many of which "buy a lot of content."

Overall, Spencer said a high tide raises all ships--so he’s not worried about competitors like the PlayStation 4 or Steam Machines.