In 2013, the AP Style Guide banned reference to “illegal immigrant”
They also do not use “undocumented”.
illegal immigration Entering or residing in a country in violation of civil or criminal law. Except in direct quotes essential to the story, use illegal only to refer to an action, not a person: illegal immigration, but not illegal immigrant. Acceptable variations include living in or entering a country illegally or without legal permission.
Except in direct quotations, do not use the terms illegal alien, an illegal, illegals or undocumented.
Do not describe people as violating immigration laws without attribution. either.
Also says children should never be described as having entered the country illegally.
I looked this up in reference to this story: Loyola Phoenix apologizes for ‘illegal immigrant’ label in murder post | Fox News
The media is supposed to refer to someone in the country without a valid visa as an “undocumented immigrant” or “unauthorized immigrant” under the newer terminology. However, much of the media refers to all immigrants as a collective group, without distinguishing between those in the country legally and those not in the country legally. Another term sometimes used is the shorter “migrant” or “migrants”.