Kate & Clint
Clint only helped a little, honestly. Kate was super skilled on her own and in some ways, as already as good at him even without the extra years for practice. But learning was always ongoing. Or something.
"Basically the next Captain America," Clint agreed easily, sipping from his coffee pot. "I hear there's an opening around here anyway." Clint hadn't known that Steve, but he was pretty much one thousand percent sure it hadn't been his version, a man he'd considered a friend and brother and grudging mentor.