They are often related though as if you have illegal money you also didn't pap taxes on it and in turn they can get you because they may not know where the money is from they know you spent more than your taxes indicate is possible.
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).
Paying taxes doesn't make illegal things legal. However it hides evidence. Al Capon was got on tax evasion because exidence of that was easier to prove. Everyone knew is other crimes - but there wasn't enough evidence to convict.
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.
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.