Kirchenkampf is a German word that means "church struggle". This happened in Germany during the time when the Nazis were in power, which was a really bad time. The Nazis did not like people who were different than them, and they especially did not like the church.
The church is a place where people go to worship and pray together. But during the Kirchenkampf, the Nazis tried to control what people could say and do at church. They even tried to make a new religion that was all about praising Adolf Hitler!
This made a lot of people really upset. Some church leaders tried to stand up to the Nazis and keep their church the way it had always been. But others started to give in and do what the Nazis wanted, because they were afraid of what might happen if they didn't.
It was a really sad time for the church in Germany. But eventually, after the Nazis were defeated, things started to get better. The church was able to be itself again, and people could worship in peace without worrying about being punished for it.