AOC, The squad are the poster children for the Democratic Ultra Progressive movement, AOC being the most notable. Problem being for Democrats, there’s a bunch of them and as much as you want to point fingers at the Religious Right & Tea Party as being out of touch with the Center - AOC, The Squad, Bernie et al. are equally off the scale.
However their ideology has slowly imbedded itself in the Democratic platform. The DNC, Democrats used to be about Blue Collar, protecting and building the middle class working man, family values. Today it’s centered around fringe interests, wealth redistribution and promoting a state and government dependent serf.
Biden hasn’t appointed any Bern’outs to his cabinet. The old guard is fighting but I doubt they’ll be able to stop the tsunami of the progressives.