What is a ProTeam in cycling?
A UCI ProTeam is a professional team in the second tier of men's road cycling, one level below the WorldTour. ProTeams can race WorldTour events only when they receive an invitation or qualify for one through the rankings.
ProTeams are fully professional: riders sign UCI contracts and must be paid at least the ProTeam minimum salary. Budgets, however, are usually far smaller than those of WorldTeams, and so are salaries.
Their calendar is built around the UCI ProSeries and .1 races below the WorldTour, plus invitations to bigger events. Organisers of the Grand Tours and Monuments use wildcard invitations to bring in ProTeams, often ones from their own country. The best-ranked ProTeams in the previous season's UCI ranking also receive automatic invitations to WorldTour races, which makes a strong ranking very valuable.
Because WorldTour licences are tied to points, the boundary between the two tiers moves. Ambitious ProTeams try to collect enough UCI points over a three-year cycle to be promoted, while struggling WorldTeams can drop down.
For a rider, a ProTeam is often the step between Continental level and the WorldTour, or a place to rebuild a career. On howtoturnpro.com you can see ProTeam rosters on a separate list from the WorldTeams.