Note that NumPy, CuPy and PyTorch are all involved in the definition of a shared subset of their API:
https://data-apis.org/array-api/
So it's possible to write array API code that consumes arrays from any of those libraries and delegate computation to them without having to explicitly import any of them in your source code.
The only limitation for now is that PyTorch (and to some lower extent cupy as well) array API compliance is still incomplete and in practice one needs to go through this compatibility layer (hopefully temporarily):