One common theme is injustice. For example, in series about real - life legal battles or false accusations, like 'Making a Murderer'. It shows how the system can sometimes fail people. Another theme is the exploration of human relationships. In shows like 'The Act' we see the complex mother - daughter relationship.
Identity is a prevalent theme too. In series that are based on true stories of people who have had to hide or change their identity for various reasons. For instance, in stories about spies or people on the run. The series often confesses how these people struggle with their true self and the identity they have to present to the world, as well as how they come to terms with it.