In fact fascism essentially has always involved a distorted parody of socialism - Mussolini was of course a prominent and active socialist before the Great War, and the very term "National Socialist" reflects that aspect. Peronism in Argentina was a variant of fascism that actually retained some aspects of genuine socialism. It's a mistake to see fascism as essentially far-right. Its primary characteristic is that it's authoritarian, most especially in relation to any popular movement it does not control.

Trumpism is very much in the tradition of fascism in many ways, most especially in drawing on the discontent of ordinary people who have lost out in recent years.