Wikipedia has a whole page on the definition of Fascism [1]. Also worth reading is Umberto Eco's article on this subject, which also has its own wikipedia page [2].
To anyone having read about Mussolini, Italy's economy and political landscape in the 20s onward, his model of corporatism etc, the answer is obviously clear: the US. China also is authoritarian, of course, but the societal structure sharply differs from Italian fascism.
Wikipedia has a whole page on the definition of Fascism [1]. Also worth reading is Umberto Eco's article on this subject, which also has its own wikipedia page [2].
Spoiler alert: it's not as simple as you imagine.
[1] https://en.wikipedia.org/wiki/Definitions_of_fascism [2] https://en.wikipedia.org/wiki/Ur-Fascism