There are a few possible reasons why your job expenses are not affecting your income tax refund amount. 

The potential reasons are:

• Your job expenses are limited by 2% of your Adjusted Gross Income (Line 37 on Form 1040).  This means only the amount of job expenses in excess of 2% of your Adjusted Gross Income are allowed as a deduction on your Schedule A.
  
• Your itemized deductions may be less than the standard deduction for your filing status.  You can find the 2016 standard deduction amounts at the following link.  You can find them on your return on Line 40 of Form 1040.  The other Forms only claim the standard deduction.
• https://www.irs.com/articles/2016-federal-tax-rates-personal-exemptions-and-standard-deductions  
• It’s also possible that you have zero taxable income.  If that is the case, then you won’t see a change for an increase in deductions.  (Line 43 Form 1040)