Each season, up to five MLS teams—four from the U.S. and one from Canada—play in the CONCACAF Champions League (CCL) against other clubs from the CONCACAF region. Two U.S.-based MLS teams qualify based on regular-season results from the previous year: the teams with the highest point total from each of the two conferences, one of whom is the Supporter's Shield champion. The third U.S. team to qualify is the reigning MLS Cup champion. A fourth U.S.-based MLS team can qualify by winning the U.S. Open Cup. If a team qualifies through multiple berths, or if any of the three MLS berths are taken by a Canadian team, the berth is reallocated to the highest-placed U.S.-based team in the previous season's overall table that has otherwise not qualified. Montreal, Toronto, and Vancouver compete against other Canadian sides in the Canadian Championship for the one CONCACAF Champions League berth allocated to Canada. Seattle Sounders FC became the first MLS team to win the CONCACAF Champions League under the competition's current branding in 2022. Since 2018, the reigning MLS Cup champion plays in the Campeones Cup, a single game against the Campeón de Campeones from Liga MX, hosted by the MLS team in September. The inaugural edition saw Tigres UANL defeat Toronto FC at BMO Field in Toronto in 2018. Another inter-league competition with Liga MX, the Leagues Cup, was established in 2019. The 2020 edition of the tournament was originally planned to pair eight MLS clubs against eight Liga MX clubs in a single-elimination tournament hosted in the United States, reviving an inter-league rivalry that previously took place in the now-defunct North American Superliga, before its cancelation. The 2023 edition will have all MLS and Liga MX teams participate. Teams The 29 teams of Major League Soccer are divided between the Eastern and Western conferences. MLS has regularly expanded since the 2005 season, most recently with the addition of St. Louis City SC for the 2023 season. The league features numerous rivalry cups that are contested by two or more teams, usually geographic rivals. Each trophy is awarded to the team with the best record in matches during the regular season involving the participating teams. The concept is comparable to rivalry trophies played for by American college football teams. Former teams Notes Timeline History Major League Soccer is the most recent of a series of men's premier professional national soccer leagues established