After you file

What?  Are you waiting for an employer to correct a 2018 W-2?   Then wait for it.  No you cannot include it when you do your 2019 tax return--that would be a big mistake.  If you do not wait for your W-2 and file 2018 without it, you will end up having to file an amended 2018 return-- a process that takes about 4 months.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**