Inglourious Basterds is entirely fictional. The director, Quentin Tarantino, crafted the story for cinematic entertainment, drawing inspiration from various sources but not real events.
Inglourious Basterds is not based on a real story. It's a work of imagination by the filmmakers. However, it might draw inspiration from historical events and settings, but the plot and characters are fictional.
Yes. While not a completely factual retelling, it draws inspiration from the fact that there were anti - Nazi efforts during the war. The idea of a group of soldiers or partisans causing chaos among the Nazis is based on the real - life resistance that occurred. But the movie's plot, like the way the Basterds operate and the specific showdowns and twists, are mostly Tarantino's fictional concoctions.