Union dues (or other job-related expenses) are not deductible on a federal tax return. W-2 employees cannot deduct job-related expenses on a federal tax return. In some states, the union dues might be deductible on the state return.
-W-2 employees cannot deduct job-related expenses on a federal return. Job-related expenses were eliminated as a federal deduction for W-2 employees by the tax laws that changed for 2018 and beyond. Your state tax laws might be different in AL, AR, CA, HI, MN, NY or PA.
https://ttlc.intuit.com/questions/4482873-which-federal-tax-deductions-have-been-suspended-by-tax-reform