Pearl Jam's Nineties track Given to Fly (released December 22, 1997, and featured on the Showtime series Roadies) lifts its verse vocal melody directly from Led Zeppelin's classic rock ballad Going to California (released November 8, 1971).
The pre-chorus vocal melody to Demi Lovato's Dance Pop single Really Don't Care (released May 20, 2014) is tonally/rhythmically similar to the intro/chorus vocal melody to Pat Benatar's 80s smash Shadows of the Night (released September 30, 1982). Compare melodies starting with the lyrics: "But even if the stars and moon collide" (RDC) VS "We're running with the shadows of the night" (SotN). Both diatonic melodies--only a half-step apart--feature a descending run followed by a single ascending note, then doubled ascending notes of the same scale (RDC in G: 1-4-3-2-1-1-2-2-3-3; and SotN in F#: 4-4-3-2-1-2-3-3-4-4).
Really Don't Care (:34) VS Shadows of the Night (:00).