I keep getting a call from a Verizon cell phone claiming it's the irs and I have the us government filing a lawsuit against me for tax fraud. This is certainly a scam?

Irs scam

Deductions & credits

The phone call is a SCAM.  The IRS does NOT telephone or email taxpayers.  The IRS only communicates through the US mail.

See this IRS website for phone scams - https://www.irs.gov/newsroom/phone-scams-pose-serious-threat-remain-on-irs-dirty-dozen-list-of-tax-s...