One of existentialism’s givens is isolation (or alienation). Another is death; we are mortal beings who inevitably perish.
In a relational universe, how can it be that we are inherently alone? This fact would imply that we each die alone, also.
Yet we come into being–are thrown into the world–birthed through the love shared by two individuals. We ultimately die, following a path shared by every living being whose lives already ceased.
We are never truly alone, contra-modern existentialism.