Christian Libertarianism is an idea that comes from Christianity (a religion) and Libertarianism (a political ideology). Christian Libertarianism tries to combine Christian beliefs with Libertarian beliefs to form an ideology that respects personal freedom and responsibility while also following Christian beliefs.
Christian Libertarianism believes in letting everybody make their own decisions. This means people should have the freedom to choose their own beliefs and lifestyles as long as nobody is harming anyone else. For example, Christian Libertarianism would not stop someone from having a different religion or gender than what Christianity usually says is okay.
At the same time, Christian Libertarianism would say that people should be responsible for their actions following Christian beliefs such as loving your neighbor and taking care of those in need. It also says that government should not take away people's religious freedom, which means the government should not be able to tell somebody what religion they have to follow.
In other words, Christian Libertarianism believes people should be free to choose their own lifestyle while also respecting the Christian beliefs of taking care of each other and respecting other people's rights and freedoms.