MD-PhD?

Just wondering, is MD-PhD just a PhD in Biological Sciences or can your PhD be in a non-science field, such as a language or music? Doesn’t have to be a PhD, but a Masters or anything else with a multiple degree program in medicine and something else such as a language or music?

Non bio MD/PhD programs exist but they are pretty rare and I’d say language/music PhDs would be even rarer or possibly non-existent. The ones I’ve seen have been non-bio sciences (i.e. computer science, engineering, chemistry or physics) or non-STEM subjects like psychology, sociology, economics, history, or anthropology. I’ve personally never heard of MD/MFA programs or MD/MA programs with a master’s in language studies but you’d have to do your own digging to see if they exist.