It is certainly a scam.
I got two very near identical messages, automateds at that that I was being sued by the IRS from:

1-202-559-8110
and
1-360-861-4613

When I called the former, I got a guy who ID'd himself as the IRS with a heavy Indian accent and asked me for my name.

I got off the phone and called the IRS number and got a recording about an ongoing scam being played out right now.

That's what I have so far.

Got a call at 7:50 am from 270-319-0000 claiming "this was officially a final notice from the IRS, Internal Revenue Service."   "The reason of this call is to inform you the IRS is filing lawsuit against you." Such bad grammar and a major scam!  I was told to "call immediately on their department number 360-861-4613." I reported the call to the FTC - FTC Complaint Assistant
https://www.ftccomplaintassistant.gov/

I just got a message saying the airs was filing suit against me.

IRS is getting ready to go after me and call this number. The call came from 727-598-9522, which caller id said was from Florida. When I "googled" it the second listing was in Russian.

keep getting a phone call from 360-861-4613 say this is the IRS  final notice/legal action
so i have read everyone's message so this is a scam