You can always get either exact copies (costs money) or transcripts (free) from the IRS for returns for the last three years (online) or older (by mail).
A transcript is a listing of all the line numbers on the various forms on the tax return with the dollars or text amounts. What a transcript lacks is the lines and boxes and shading of the actual form (the numbers are, of course, all you need in most cases).
Go to the IRS's Get Transcript site, read the instructions and the FAQ and get your 2015 transcript.