Lee was killed on November 2, 2015 in an alley near Dawes Park on the South Side. Prosecutors said the child was targeted because of his father's gang affiliation.
Three alleged gang members, Corey Morgan, Kevin Edwards and Dwright Boone-Doty, will stand trial starting in April.
Police said Morgan lured the child into the alley where Boone-Doty shot him several times. Edwards is accused of driving the get-away car.