Collins died Saturday of natural causes, Davis, who replaced Collins when she retired in 1997, said in a statement.
"Cardiss Collins was a serious advocate for women and working people," Davis said.
Collins represented Illinois' 7th Congressional District for nearly 25 years and led the Congressional Black Caucus from 1979 to 1981.
"We will no longer wait for political power to be shared with us. We will take it," the Chicago Tribune reported Collins once said at a fundraiser.
She joined Congress after winning a special election to replace her husband, U.S. Rep. George Collins, who died in a plane crash at Chicago's Midway Airport in 1972.