Tête de la Course translates to the leader of the race. It refers to the rider or riders in front in a cycling stage.
You might hear this a lot while watching professional cycling races on TV, particularly the Tour de France. The leaders in the race, whether alone or in a small group, are referred to as being in the “Tête de la Course” to indicate their position. It’s a good position to be in, particularly on large stages, and tends to receive more camera time, commentary, and crowd applause. This is also where the action takes place, with attacks, pursuits, and the race-deciding moments.