Origin of "CK"
It's how his original last name is pronounced. Dad is economist Luis Székely. Mom was Irish American. So Louis CK could claim to be Jewish-Catholic American-Mexican-Hungarian!
https://en.wikipedia.org/wiki/Louis_C.K.
https://hungarytoday.hu/hungarian-roots-us-comedy-star-louis-c-k-szekely-22004/
His parents, Marie Louise Székely (née Davis) and his father Luis Székely met at Harvard University. Mexican-born Luis earned a degree from the National Autonomous University of Mexico prior to graduating from Harvard. C. K.’s paternal grandfather, Dr. Géza Székely Schweiger, was a Jewish Hungarian surgeon whose family emigrated to Mexico, where he met his Catholic wife.