A janitor who’d worked 40 years at Arrowhead Stadium found a letter in his locker after retirement — signed by Travis Kelce and Taylor Swift. Inside was a handwritten message: “You’ve cleaned up after our wins; now let us clean up your future.” — and a set of house keys no one knew about.

A janitor who’d worked 40 years at Arrowhead Stadium found a letter in his locker after retirement — signed by...