The Nazi Party charter, point 24: "The Party as such advocates the standpoint of a positive Christianity without binding itself confessionally to any one denomination". Their charter does go on to demand religious freedom for religions that do not offend the morality of the German people (Christian morality).
The dominance of Christianity was so profound in the Nazi party that the Potsdam Church was (is) a well known symbol for the Nazi party. The first series of Nazi minted silver coins (1933) featured the Potsdam Church on the obverse side of the 5 Mark silver coin and Martin Luther on the obverse side of the 2 Mark silver coin.
Prior to WWI, with a few regional exceptions, being a Christian was a requirement for German citizenship. A person could simply not be a German citizen unless they proclaimed devotion to an approved Christian sect. Not long after Jews were allowed to become German citizens on a national scale, WWI broke out. Thus, when Germany lost the war, it was a common Nazi Party claim that "Jewish treachery" was responsible as they had not "lived up" to the perceived additional responsibility of being German citizens.
Pope Pius XII was the leader of the Catholic church before and during world war 2. He is sometimes accused by writers, such as John Cornwell, of not doing enough to publicly oppose the Nazi regime. His defenders point out that he spoke out against war but was limited in what he could achieve, given that Italy was allied with the Nazi government. Pius XII provided discrete assistance to Jews, resistance fighters and allied forces.
"[Pius XII] had so little scope of action that it is impossible to judge the motives for his silence during the war, while Rome was under the heel of Mussolini and later occupied by Germany. ... But even if his prevarications and silences were performed with the best of intentions, he had an obligation in the postwar period to explain those actions"
- — John Cornwell
The pope's actions compares poorly to (exceptional and rare) Christians such as Dietrich Bonhoeffer, who opposed the Nazis on moral grounds and was executed as a result. Partly due to the secrecy of the Vatican, the exact events surrounding Pius XII are still secret and remain controversial to this day.