Money launderning is making it look like the taxes have been paid.
After you pay your W2 income taxes for the year, your income for the year is no longer taxable.
edit: I guess I can't argue with the holy writ of wikipedia, but it's how they got Al Capone.
Related but entirely different purposes. Paying taxes on illegally sourced money is basically the goal, because it makes it legal - it gives you a declared income and means future transactions look within your means.
Tax evasion conversely makes legally earned money somewhat illegal to the evader (though generally fine for anyone else to handle accidentally).
Just using an unlicensed hawaladar to transmit legally earned and taxed money is money laundering (whether that is the actual statute that would be charged, idk, but it falls under the stuff AML compliance is supposed to catch). The whole system is absolutely insane.
That’s tax evasion.
Money laundering is disguising the source or use of funds (making illegally sourced cash look legally sourced).
Plenty of people would (do) happily pay some tax on cash as part of avoiding difficult questions about the source.