If you used the desktop version (CD/download) to prepare your 2015 returns, then they will not be in an online Tax Timeline. The desktop version stores the files locally on your computer.
Search your entire system for any file ending in *.tax2015, which is the data file. Also search for any PDF files of your 2015 return that you may have saved.
If you don't find any 2015 tax files on your computer, you can download a free 2015 tax return transcript at this IRS website:
http://www.irs.gov/Individuals/Get-Transcript
A copy of the actual return from the IRS costs $50 and takes several weeks.
