Pyenv has nothing to do with pipenv.

Pyenv is mainly for installing versions of Python. It's useful if you work on multiple packages that each needs a different version of Python, or if you have one package that you test with multiple versions of Python. (Alternative to apt/yum/brew or manually downloading Python from python.org)

pipenv is for installing Python packages for your project. (Alternative to pip, poetry, etc)

I believe pipenv is a wrapper around pip and pyenv.

Pyenv is brilliant, defiantly recumbent it as the standard way to manage python versions. It's basically nvm but for python.

Pyenv is a bit lower-level and works well with requirements.txt. Pipenv can use pyenv to install Python venvs and brings its own Pipenv and lock files.