It includes allies. This is because of the tyranny of distance. US simply cannot power project enough to take on China with Taiwan alone.

https://www.cnn.com/2023/01/09/politics/taiwan-invasion-war-game-intl-hnk-ml/index.html

But these war games are actually biased towards USA. Pentagon's own war games have China winning already.

https://news.yahoo.com/were-going-to-lose-fast-us-air-force-held-a-war-game-that-started-with-a-chinese-biological-attack-170003936.html

So if we believe the US military, then China can already win. Though many argue US military says this just to get more funding.

I would err on the side of US just barely winning with all allies.

That said, I do not believe China would invade. It makes no sense. Anyone who claims this is could happen should have their credibility questioned. As China as I said already has shown its hand, it will blockade if it comes to it.