This is pretty bad journalism and just kind of meant to stoke the fire of controversy. The subpoena will most likely be dropped (as ICE would with almost certainty lose in court[1]).

The Yale Law Journal article cited does argue that even though it's worrysome that there's no federal reporter's privilege, there's plenty of precedent, including constitutional (state-level), statutory as well as common-law protections that can be invoked to throw out this kind of lawsuit.

[1] https://www.yalelawjournal.org/article/the-de-facto-reporter...