Does flask and django work together, should I learn them simultaneously?

  backend, django, flask, node.js, python

I recently learned Django & I wonder if I have to learn Flask in order to have a good back end stack?
I know Node.js and used it for APIs before but I don’t know if it should be mixed with Django in a single project or not.

Thanks in advance.

Update: I am thinking APIs & Socket wise because I don’t feel like Django supports them (Please correct me).

Source: Python Questions