Federally, this is no longer deductible once the Tax Cuts and Jobs Act eliminated the Miscellaneous Deductions that included Unreimbursed Employee Business Expenses. Please check out the 2019 Instructions to Form 2106 if you want to learn more. There are limited circumstances that may still allow for a deduction on the federal return.
Depending on your circumstances, the nature of your business, and your state of residency, it may be deductible on your state return for a a limited number of situations.
Go to your state's Department of Revenue site to learn if unreimbursed employee expenses are still deductible. A handful of states, such as those listed below, do still allow a deduction for unreimbursed employee expenses:
Arkansas residents
California residents
Minnesota residents
New York residents
Pennsylvania residents