I want to know, why human die? What is the meaning of life? I could die tomorrow. What's the meaning of all these things?
Not only humans die. Other animals die too.
From the perspective of evolution dying of old animals gives way to a new generation, better adapted to a changing environment.
I do not recognize a higher meaning of life. Nature exists billions of years without animals. Nevertheless from the perspective of the single human individuum: We are able to choose a meaning for our own life. And if we are fortunate, then we succeed in doing so.