Underdogs have a lower win probability, usually for the same reasons.
Favorites have a higher implied probability of winning a game due to a number of factors, including skill, matchup factors, and sometimes home-field advantage.
The most basic moneylines are a two-way market involving a favorite and an underdog. Moneyline betting is one of the three most common ways that people bet on sports, along with point spread betting and Over/Under betting. Moneyline odds are very popular with new sports bettors because you’re simply picking which side will win. It's an easy-to-understand bet that's perfect for beginners and seasoned bettors alike. The goal is to pick the winner, and that's it. In this type of wager, bettors choose a team or individual athlete, like a tennis player, to win a game or match.
Moneyline betting is a simple and popular way to bet on sports.