A phrase noting that some things are unavoidable, like mortality and paying taxes. It means certain facts of life cannot be escaped.
Certainty? In this world nothing is certain but death and taxes. Benjamin Franklin
The only difference between death and taxes is that death doesn't get worse every time Congress meets. Will Rogers
Nothing in the world is certain except for death and taxes. Benjamin Franklin
Nothing is certain but death and taxes. Darkovan Proverb
Death and taxes may be hard to beat. American Proverb
Nothing is certain but death and taxes. Traditional Proverb