I'm still waiting for my W-2 to come in the mail. Can I file without it? Does Turbotax already have access to that W-2 form before I do?

Yes. You may file without a form W2 by using a Substitute form, The Form 4852 is available on 2/18/2020.The form 4852 is a substitute for form W2, W2-c, and 1099-R  The employers are required to mail tax forms by February 1, 2021. If you haven't received your W2 by February 15, 2021, you may have to contact your employer or the IRS at 1-800-829-1040 for a substitute.form  

Thank you so much for your helpful response. I appreciate it.

The current form (Sep 2020) says it can only be filed after calling IRS and waiting for them to send a form. I have income from an entity abroad that will never send a 1099. Still necessary to call? Or just mail it anyway from Turbotax? Or will the form be changed to remove the calling requirement? Thank you for answering.

@hanspu

This is a different scenario than the original posting.  Since you're talking about reporting income from a foreign entity, different rules apply.

Please see the TurboTax Help article Do I need to report foreign income? for guidance in entering this foreign income.