Looks like I'm going to be near Chicago in a week or so for a few days.
I'm not going to be bringing any guns but I was wondering about knives.
Right now I was just planning on having a simple lock back knife with me.
Thinking spyderco Delica 4.
Anyone have any input?
Thank all.

IANAL

Don't be an asshat and you'll be fine. Automatics are legit here.

Only exception is a place with a metal detector - avoid them.

I am pretty sure, and this link corroborates it,  that automatic knives are only ok if you have a foid card.

https://www.tektogear.com/blogs/news/illinois-knife-laws-updated-2020-are-knives-legal-in-the-prarie-state

Correct.   And state does not have preemption so there's a hodgepodge of various knife laws across municipalitiies.   You should be fine as long as not using to commit a crime or do something stupid.  Most blade lengths of 3" or less are what I've seen in most laws.  Spring assisted in addition to automatic are ok.

SB0607  IL criminal code:

https://www.ilga.gov/legislation/publicacts/fulltext.asp?Name=100-0082

(e) Exemptions.

       (2) The provision of paragraph (1) of subsection (a) of
   this Section prohibiting the sale, manufacture, purchase,
   possession, or carrying of any knife, commonly referred to
   as a switchblade knife, which has a blade that opens
   automatically by hand pressure applied to a button, spring
   or other device in the handle of the knife, does not apply
   to a person who possesses a currently valid Firearm Owner's
   Identification Card previously issued in his or her name by
   the Department of State Police or to a person or an entity
   engaged in the business of selling or manufacturing
   switchblade knives

I thought I read that non-residents are exempt. Apologies for any confusion.

IIRC, just right before the non restricted bill was about to pass, there was a stabbing in Chicago with a switchblade.  Of course to protect us all, the ILGA reps had to add in the FOID requirement.