DAREDEVIL #43, 1968, inked by Joe Sinnott. I guess the Captain America guest appearance was the impetus for bringing Kirby back on DD covers for one issue several years in. Whatever the reason, that's a great action pose for the two characters. You can see why Kirby was so often employed to do covers for books he didn't draw interiors for.
Regular DD artist of the time Gene Colan did an unused cover to this issue, with DD more prominant than Cap (and giving Cap a whupping). You can see a version of it here. So presumably the Kirby version was commissioned either to give Cap a larger place or not having him as the underdog.