Conversation so far:
who won the national college football championship this year
The 2020 College Football Playoff National Championship was won by the LSU Tigers.
What team did the LSU Tigers defeat at the 2020 College Football Playoff National Championship?
The 2020 College Football Playoff National Championship featured LSU Tigers defeating the Clemson Tigers.
What was the score for the 2020 College Football Playoff National Championship
The score of the 2020 College Football Playoff National Championship was 40 LSU to 25 Clemson.
Were any records broken at the 2020 College Football Playoff National Championship?
2019 LSU Tigers claimed the second 15–0 season among any team in the modern era.

Question: Who were the first?
Self-contained rewrite: Who were the first team to win 15 games in the modern era of college football?