Steve McQueen is Dr. Gregory House's pet rat in the US TV series "House" (November 2004—May 2012). The rat (McQueen) use to be a resident in Stacy Warner's home. In order to try to impress Stacy, House hunted for the rat in her home. Stacy was a lawyer working at House's hospital; she has a relationship with House.

When House found the rat, he noticed that Steve appeared to be ill; Steve was turning his head to the side, which is not considered normal behavior for a rat. Instead of killing him, House eventually captured and named the rat. He then fully treated him.

House ultimately took Steve McQueen to the hospital for treatment. House's friend and associate Wilson was at first shocked and feared for the health of the patients. House however quite quickly pointed out that any disease that is contagious to rats isn't passed on to humans. Eventually, after Wilson moved in with House, he became attached to Steve McQueen as well. In fact, when House decided to use Steve McQueen as a guinea pig when Foreman (a neurologist and once senior fellow working for House) became sick in the episode titled "Euphoria: Part 2", Wilson was aghast and asked House why he couldn't use a lab rat. House said he needed a rat he was sure was healthy. In the end, Steve McQueen luckily survived the exposure to what affected Foreman.

To conclude, McQueen presumably died due to old age as rats seldom live longer than 3 years.

More Info: house.fandom.com