If you can be persistent and get it from the employer, that's the easiest solution. Can you stop by the employer's business and pick it up?
Another approach is to talk to the IRS and ask them to help you get it from the employer, and they will contact the employer and do a little "encouraging." If you talk to them, the IRS will need some info from you. See this page at the IRS website:
https://www.irs.gov/taxtopics/tc154
Here's additional info in a TurboTax FAQ:
FAQ: What if I don't have my W-2 by February?
https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/february-still-w-2/L1jh6HaiP_US...
If push comes to shove, you might be able to file using a substitute W-2 as mentioned in both of those articles. If you do that, you have to file on paper with Form 4852, and you may have to amend the return later when you get the actual W-2.
