The duo that has dominated European football for the past 15 years—Cristiano-Messi, or Messi-Cristiano—is nearing the end of what seemed like an endless run. Others will have to take up the slack now that both are enjoying football in lower levels outside of Europe. That is where Kylian Mbappe and Erling Haaland come in, two of the players (there are more: Bellingham,…