How to study relationship between two categorical variables when number of categories is very high?



Hello everyone,
I am trying to explore a data set in python with around 1 million data points. I have to columns ‘user_id’ which defines a particular user and a ‘genre_type’ which defines the type of genre the user listens, both of them represented as numbers. As per my understanding, I should treat both of them as categorical while exploration. I want to study the relationship between them by using graphs. The problem lies in the fact that there are around 20000 unique users and 200 unique genres. Which plot can I use to properly study them together. Also, mention if there is any other technique.