Both Marcus Garvey and W. E. B. Du Bois challenged the accommodationist ideas promoted by the very influential figure Booker T. Washington. Washington advocated for blacks to accept second class status in the U.S. in return for economic gains, arguing that once the black community had an economic base and some wealth, white society would be forced to open up full rights to it.
Both Garvey and Du Bois used visions of the international community to counter Booker's ideas. Garvey forcefully argued that blacks should not give up their dignity by accepting inferiority to whites in U.S. culture, and he told blacks they had another choice to knuckling uder: immigration back to Africa. He was a great proponent of this migration back, although very little actually occurred. Nevertheless, the vision was potent and helped fuel black separatist movements in the US, such as Nation of Islam, and black pride. Interestingly, Malcolm X's father was a disciple of Garvey.
Du Bois was born a free black, unlike Booker, and was educated at Harvard and, notably in Berlin, so that he was a cosmopolitan scholar well versed in other languages and cultures. He used his broader, internationalist perspective to advocate for full equality for US blacks without compromise. In his highly influential book, The Souls of Black Folks, he marshals his knowledge of European history to argue that accepting inferiority has a debilitating effect on an ethnic group, using the present day Greeks as an example. Because of his wide knowledge of the world, could envision educated blacks across the globe spreading ideas of equality.