What happens to IRS Lien if it's not redeemed ?

What happens to the IRS Lien if the IRS doesn’t redeem within 120 days ? Does it get wiped out or stay on the property ? For how long?

It is wiped out at the time of sale – except for their right to redeem. If they fail to redeem they no longer have a secured interest in the property (though they can certainly continue to pursue the prior owner).