Coldfusion - Python WebApp networking question

We had a question come in for consultation and I’m not sure where to start so I’m asking for thoughts and resources if anyone can share:

What is the best and most secure way to let ColdFusion web 
application to listen to a python web application on the same 
network? Should it be better to arranged in different 
servers or on the same server? How to encrypt the traffic 
and only allow internal visitors? Should I use container 
(I am concerned about security)?

Thank you so much for any guidance, including good questions to ask the client.