It is simple to extend human life. Travel fast through space and you can live almost forever (providing you don't hit anything).

You are kinda already an example for living forever.

How?

You are moving fast through space.

In reality, your entire lifetime is already over but because you are relative to the motion you created a small infinity for yourself.

Move even faster and that infinity grows.

Match the speed of light and maybe you are god as you live truly forever for death can't catch up.