The Tramp is one of the titular characters in Disney’s 1955 animation and 2019 live-action Lady and the Tramp films.
In the animated film, the Tramp is definitely part Schnauzer. He is grey in colour with a distinctive fuzzy snout. However, he’s referred to as a ‘mutt’, and is probably mixed with a terrier. He’s voiced by Larry Roberts.
In the live-action film, the Tramp is played by a mixed-breed dog called Monte. According to the New York Post, Monte is most likely to be a mix of Schnauzer and shepherd.
Source: https://nypost.com/2019/11/06/meet-the-real-dogs-of-disneys-new-lady-and-the-tramp/