In 2008, their 79th season, the Lions became the first NFL team to finish winless once the regular season expanded to 16 games. They finished with an 0-16 record.
In 1976, the Tampa Bay Buccaneers were the NFL’s first winless team once the season expanded to 14+ games with an 0-14 record. Meanwhile, the Cleveland Browns were 0-16 in 2017.