This is the first time I heard his name, so that's also a TIL for me. Not everyone follows US internal news that closely.

Mahmoud Khalil, a student activist and negotiator in the 2024 Columbia University pro-Palestinian campus occupations, was taken from his home by U.S. Immigration and Customs Enforcement (ICE) agents on March 8, 2025 without having been charged with a crime.

https://en.wikipedia.org/wiki/Detention_of_Mahmoud_Khalil