Radiation Immunity – The ability to not suffer from the ill effects of radiation.
In Avengers V1 #8, Kang the Conqueror (Marvel) informs the Avengers that all inhabitants of the 40th Century have radiation immunity.
As a human, Lex Luthor can wear a kryptonite ring whose radiation keeps Superman at bay. However, Lex Luthor does develop cancer because of the ring eventually.
In the DC Silver Age you could glow due to radioactivity but not die (Detective Comics V1 #301, Jimmy Olsen V1 #17)!