Metallica asked Turnstile to tour with them and were told no. James Hetfield said so himself, on his SiriusXM show Riff Life, and he did not say it as a complaint.
"We have seen them live, we wanted to get them on tour, and they said no," he said. "They're doing good on their own already. But man, what a vibe they bring. They are so fun. Go see them play if you can."
That last clause is the whole story. A hardcore band from Baltimore is now large enough that opening stadiums for the biggest band in metal is not obviously the better use of a year, and the people who offered it agree.
Hetfield also made the point most bands of that size resent being made about them. "Just like many, many bands, they sound great on their records and recordings, but man, when you see them live, you totally get it."
The interest is not new. He was seen watching them from the side of a stage at a Norwegian festival in 2024, next to Rob Halford of Judas Priest. And the scale is not theoretical either: Turnstile drew around sixty thousand people to the National Mall this autumn.