I imagine hes is misquoting the United Front here?

The United Front (Einheitsfront) was the strategy of the German communist party KPD to counter both fascism and social democrats (whom the KPD and the Third International called social fascists (“Sozialfaschisten”)). As you can probably guess, this wasn’t very successful in uniting the left and center against fascism, so Parties of the Comintern ended up changing strategies to the United Front, a broad coalition of left and center against fascism. This had some limited success (France had a Popular front government of communists/socdems/left leaning liberals for two years that enacted a fairly large amount of very progressive labour laws and banned a number of fascist and monarchist organisations like the Croix de Feu, Spain had a similar Popular front which ended with the military loss in the civil war against Franco)

The SocDems SPD had a similar strategy btw., the iron front, which intended to counter fascism, monarchism, and communism and was opposed to the KPD.