If you had no physical presence in the U.S. during 2016 and no U.S.-source income, whether you have to have file a U.S. return will depend whether on whether you are U.S. citizen or resident alien (green card holder) on one hand, or a nonresident alien, on the other hand.
The IRS subjects U.S. citizens and resident aliens to U.S. federal income taxation on their worldwide income, wherever earned, allowing for certain exclusions for foreign income and housing, and credit for foreign taxes paid on the same income.
However if you qualify as a nonresident alien for U.S. federal income tax purposes and have no U.S.-source income, you will likely have no U.S. filing requirement.
For more
information about nonresident alien status versus resident alien status, please
see IRS Publication 519, US Tax Guide for Aliens:
https://www.irs.gov/pub/irs-pdf/p519.pdf
