He's retiring and a Republican will win the election to replace him.
TBH, Marchant is a stronger candidate than any other local Republican would be. They'd be crazy to replace him and have the seat be an open seat. At least he has
some name recognition: there are people who pass exit signs for Marchant Boulevard every day on their commute. (I only mean this last part half-jokingly: given how little the guy does, the highway exit named after him is the main way people will encounter his name, but it is at least
a way they're encountering his name)