Vocal jazz couldn’t ask for a better ambassador. Laufey first broke through on TikTok with her jazzy covers of Billie Eilish and Taylor Swift. But it’s her original songs that are now appealing to Gen Z, and a wider audience. A graduate of Boston’s prestigious Berklee College of Music, the young Icelandic artist has found success with her tastefully anachronistic arrangements and contemporary lyrics. Her second album, Bewitched, became the best-selling jazz album on Spotify (5.7 million streamsin one day!). This year, she also won the Grammy Award for Best Traditional Pop Vocal Album, a category previously awarded to Frank Sinatra, Tony Bennett and Joni Mitchell. Laufey’s second appearance at the Montreux Jazz Festival will be on the Casino stage, where Ella Fitzgerald, one of her great heroes once played.