Yes, depending on what kind of content you are looking for, there may or may not be a subscription required. You can do a search in the Roku app store. Certain local Fox channels are available for free for local news broadcasts, other Fox channels require a subscription/provider.
@meilizhang, not for free.
Yes. It used to be carried for free, but a year or two ago Fox decided to make their streaming app only available for those already paying for it as part of a paid subscription to a "tv provider" account (primarily cable or satellite).