Who/What is "The New Colossus" in Wolfenstein 2 the New Colossus?

There is no official explanation from the developers, but there are strong indications that this refers to the Poem of the same name by Emma Lazarus from 1883. This poem was written to raise money for the construction of the pedestal the Statue of Liberty is perched on. BJ Blazkowicz also quotes this poem at the end of the first game:

In this context, "The New Colossus" most likely refers to the United States of America, and the rebirth of this "colossus" of old after being conquered and broken by the Third Reich.