Mahmoud Khalil's detention ignited fierce debate over the Trump administration's immigration crackdown and free-speech rights.

"This vindicates what Mahmoud has maintained since day one — that the government cannot detain or deport him based on Rubio’s say-so," Ramzi Kassem, a lawyer for Khalil and a law professor at the City University of New York, said in a statement.

Mo Amer, Mark Ruffalo, Mahershala Ali, Tom Morello, W. Kamau Bell, Arian Moayed, Dallas Goldtooth and Alex Winter came together on behalf of Mahmoud Khalil and his family to call for his freedom