Robert De Niro delivers an exceptional performance within this somber and realistic portrayal of ex-marine "Travis Bickle." His days are consumed by solitude – driving a taxi through the night and then watching films during daylight hours. This repetitive pattern is disrupted when he becomes interested in "Betsy" (Cybill Shepherd), who works on the campaign for an aspiring US President. A moment of optimism arises as she consents to accompany him to a movie, but that quickly fades when he brings her to his preferred venue for a Swedish film that didn't quite live up to Ingmar Bergman’s standards, leaving him where he started. At the same time, he develops a protective feeling toward "Iris" (Jodie Foster), a young prostitute being exploited and mistreated by her pimp. Consequently, he obtains some weapons with which he is skilled, ultimately finding a reason for his previously aimless life. Director Martin Scorsese and composer Bernard Hermann have crafted a remarkably believable and affecting setting that highlights the unpleasantness of nighttime New York, an environment where De Niro truly excels. He conveys a feeling of vulnerability alongside a sense of moral character; he possesses integrity despite the apathy surrounding him. By the film’s conclusion, I was completely on his side. Experiencing this movie in a theater is highly recommended – it significantly enhances this wonderfully atmospheric and powerful work of cinema.

Source on TMDB