Chicago police said the man had just gotten into the back seat of a rideshare car just after 1:45 a.m. when a gray Volkswagen sedan pulled up next to it, near 75th Street and Jeffery Boulevard.
A male suspect shot at the man, hitting him in the head.
The rideshare driver went to a gas station in the 2300-block of East 75th, and flagged down officers, who were responding to a ShotSpotter alert.
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The man was pronounced deceased on the scene, CPD said.
The alleged shooter's vehicle crashed into an unoccupied parked car in the 7500-block of South Clyde Avenue, and the suspect took off on foot.
No one was in custody later Thursday morning, and police said the victim was not known to police.
Area Two detectives are investigating.