As of Jan 1, 2021, you may no longer be able to pump your own gas in Illinois.

Legislation proposed by Illinois House Democrat Camille Y. Lilly was introduced into the Illinois General Assembly on Feb 5th and it states:

Creates the Gas Station Attendant Act. Provides that no gas may be pumped at a gas station in this State unless it is pumped by a gas station attendant employed at the gas station. Effective January 1, 2021.

If passed and signed into law, Illinois motorists would have to wait for an attendant to pump their gas at all Illinois gas stations.

Oregon and New Jersey are the only other states that ban self-service gas stations in some capacity.  Oregon just relaxed their rule to make it easier to pump their own gas if living in rural areas.

Rep Lilly represents Oak Park Illinois near Chicago and has not stated why she is proposing the law which is currently sitting in the Rules Committee.