Ecently found tax return for 2016, can i still file? will it at all affect this years return? and if so, how?

[JohnW15]

If you haven't filed your 2016 return yet, you can still file it.  It won't affect this year's return. 

If your 2016 return will result in a refund, you must file it by April 15, 2020 .  If it results in a balance due, you should file it as quickly as possible to minimize any penalties and interest.