If you used TurboTax Online, the 2015 servers (and
those of earlier tax years) have been shut down and the data has been deleted.
If you didn’t save a PDF copy of your 2015 return, then you can look up the
information via the CRA: https://turbotax.community.intuit.ca/replies/2647704
If you used TurboTax CD/Download in 2015, then the
files were saved to your own computer and we don’t have copies of it. Here is
some information that may help you find your files if you used TurboTax
CD/Download in previous years:
https://turbotax.community.intuit.ca/replies/3285180