F.O.I.D. law has not been struck down. Thus for Illinois residents you'll still need the card to remove a gun from your home.
For Chicago residents. Most city gun ordnances will be out the window. Probably take a court case to prove it.
From what I can tell our Illinois FOID card is harder to get than most states CC permits. Just as effective today is our enhanced drivers licenses. The way I understand it LEO's can scan the bar code to see everything government has on you. If you've been ordered by a court not have firearms it shows up. FOID IMHO is out dated. I paid a pile of money to get a photo for my last renewal then they just used my DL photo which was older but a mouse click away. In 1968 when FOID was pushed upon us we didn't have photo drivers licenses. Or computer data bases. Or cell phones that scan bar codes then hook up to a huge computer.