Cassini is now part of Saturn.
Eons from now, when we live no longer, our galaxy and Andromeda will merge.
Cassini will be there.
And when Saturn is no longer, its fragments ejected into space, Cassini will too.
Another star will make use of Cassini's remains. And there might be other lives that wonder where their star came from and what it is made of.
They will never know of Cassini, but it will be there.