My husband is a truck driver but w2. He has expensive due to doing his job. Why are they not deductible?

Sorry they changed it back in 2018.  W2 employees can no longer deduct employee job expenses.  

FAQ on changes

https://ttlc.intuit.com/community/tax-reform/help/how-will-tax-reform-affect-my-federal-tax-return/00/27627

Deductions that have been suspended for 2018-2025

https://ttlc.intuit.com/community/tax-reform/help/which-federal-tax-deductions-have-been-suspended-by-tax-reform/00/25565

Congress changed the tax laws so write letters of complaint to each of your congresspeople.

He can deduct the expenses if they are true not reimbursed employment expenses. This is done under deductions and credits turbo tax.

Sorry---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