Ok I have to guess that all three haven't seen the movie cause you didn't give enough info.
Stalag 17 (1953, note it is in black & white in case some are allergic)
Available on Amazon Prime (probably elsewhere too)
Don't search for info about it or you'll get the ending spoiled!
One night in 1944 in a German POW camp housing American airmen, two prisoners try to escape the compound and are quickly discovered and shot dead. Among the remaining men, suspicion grows that one of their own is a spy for the Germans. All eyes fall on Sgt. Sefton (William Holden) who everybody knows frequently makes exchanges with German guards for small luxuries.
The Confession (1970)
Preview. Available on YouTube.
The Confession (French: L'aveu) is a 1970 French-Italian film directed by Costa-Gavras starring Yves Montand and Simone Signoret.
It is based on the true story of the Czechoslovak communist committed leftist Artur London, a defendant in the Slánský trial. Gavras did not intend the film as an anti-communist film but as a plea against totalitarianism and particularly Stalinism.
Black Robe (1991) Amazing soundtrack. Sort of a more gritty depressing Dance with the Wolves.
Available on Amazon Prime
In the 17th century a Jesuit priest and a young companion are escorted through the wilderness of Quebec by Algonquin Indians to find a distant mission in the dead of winter.
www.primevideo.com
Trailer
Set in 1634, this film follows the travels of Father LaForgue (Lothaire Bluteau), a Jesuit priest called upon to search for a remote Canadian mission surrounded by Huron settlements. LaForgue, guided by a group of distrustful yet kind Algonquin natives, embarks on a trek across unfamiliar and treacherous terrain.
The Conformist (1970, incredibly beautifully shot, beautiful soundtrack, must be seen in Blu-Ray/HD stream)
Available on Youtube.
Trailer (rather spoilery!)
Marcello Clerici (Jean-Louis Trintignant) is a member of the secret police in Mussolini's Fascist Italy. He and his new bride, Giulia (Stefania Sandrelli), travel to Paris for their honeymoon, where Marcello also plans to assassinate his former college professor Luca Quadri (Enzo Tarascio), an outspoken anti-Fascist living in exile. But when Marcello meets the professor's young wife, Anna (Dominique Sanda), both his romantic and his political loyalties are tested.