The base is original from the producer (chords and melodies), but is complemented with elements that complement the song that come from samplepacks, usually, vocal chops, guitars, wobbles sections, glitch effects. It is the standard in which most of producers work, in a project you will find MIDI files made by the producer, but also melodic loops.
I did the bassline and the drums session, then I just completed the song with vocals and sfx.
Instrument Vocal Choir
Sample pack Splice Originals - Silk & Soul with the Splice Gospel Choir
Loop name SO_SS_140_vocal_riff_hooah_tender_vocoder_Am