Here's a link to Wisconsin form W-220:
https://www.revenue.wi.gov/TaxForms2017through2019/w-220.pdf
If you're an Illinois resident who works in Wisconsin, your W-2 wages or salary are not subject to Wisconsin income tax, but they are fully taxable by your home state of Illinois. Since you pay no tax to Wisconsin, there is no "other state credit" to be had.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
