Earlier quoted context omitted.
He may issue an EO against them similar to the ones he's successfully used to bring major law firms he doesn't like to heel: ban consideration of former Harvard employees (... maybe also graduates?) for Federal jobs, revoke clearances held by anyone employed by Harvard, and ban them from Federal property. Maybe with some other creative terms thrown in to mess with universities in particular.
That is always a risk of working for the government. Your job exists more or less at the whims of the currently governing administration.
Or we didn't. Now we do. Kinda sucks.