In Thybulle's second season with the 76ers, the forward solidified his role as a lockdown defender. The 24-year-old posted season averages of 3.9 points, 1.9 rebounds, 1.6 steals, 1.1 blocks and 1.0 assists. Thybulle played in 65 games and started in nine of those, averaging 20.0 minutes of run. The forward was able to hit 42.0 percent from the field, 44.4 from the charity stripe and 30.1 percent from behind the three-point arc. In the playoffs, Thybulle averaged 5.3 points, 1.4 rebounds, 1.3 steals and 0.9 blocks in 18.3 minutes. He recorded one of his best games of the season against the Wizards on May 26, as Thybulle logged four steals and five blocks in 20 minutes of action. The forward also matched a career-best five steals against the Bulls on March 11. In the regular season, Thybulle led his team in steals (1.6) and finished second in blocks (1.1). Offensively, the former Washington product snagged five double-digit scoring performances, as he made an efficient 70.6 percent from the field in those games. The 6-foot-5 Thybulle became a better rebounder in his sophomore season, when he logged 60 games with at least one rebound.2019
The 20th overall pick in the 2019 NBA Draft appeared in 65 games for the 76ers, making 14 starts. In 19.8 minutes per game, Thybulle averaged 4.7 points, 1.6 rebounds, 1.2 assists, 1.4 steals and 0.7 blocks. Thybulle made his NBA debut on Oct. 23 against Boston, finishing with three points, one rebound, one assist, two steals and two blocks. He scored a season-high 20 points in a win over the Raptors on Dec. 8, drilling five three-pointers and going 3-of-3 at the line. On Dec. 5 against Washington, Thybulle handed out a season-best six assists. He had at least four steals on six separate occasions, including a season-high five steals against the Lakers on Jan. 25. In a win over Brooklyn on Jan. 15, Thybulle blocked a season-high four shots. The rookie appeared in all four of Philadelphia's matchups against Boston in Round 1 of the playoffs. In Game 1, Thybulle posted five points, four rebounds, one assist, two steals and a block. Thybulle finished the season ranked 15th in the NBA in total steals (94), 17th in steals per game (1.4 SPG) and second in steal percentage (3.5%).