All prerecorded, Dan. They used to record the music and the performer would sing, but even that went away about 8 years ago. I think Red Hot Chili Peppers was the last band that sang live over prerecorded music. They showed some closeups and people took still frame captures of Flea playing his bass with the output jack on his bass completely empty. In this case I don't even know what Weeknd or Dwntown or whatever his deliberately misspelled name is does, nor did I care much to find out.

I think the last halftime show I watched was Bruno Mars.