You'd be surprised. There is quite a bit of polymorphism within the human species that is very much distinguishable per population. E.g. haplogroup analysis or microsatellite analysis is remarkably accurate in this regard due to a lack of interaction between far flung populations until quite recently in human history. Now, does this imply all the bullshit eugenicists and other racists tend to preach about with race? Hell no, social factors are responsible for most of that variance, but to suggest there would be no biomarker for "race" in its colloquial definition as proxy for population of origin is inaccurate.

This is also why there is a big focus now to seek out underrepresented populations in genetic analysis, because there may be population specific biomarkers that are relevant in disease that you miss if you limit yourself to the handful of widely sequenced homogeneous populations (e.g. there are Utah and Iceland datasets that are popular to use for this).

"Races don't exist biologically"

This being your first sentence doesn't warrant continued reading.

Humans are animals, adaptable animals. We have seen how pigment faded when people moved out of Africa and the energy cost of melanin was saved as men lost melanin to allow Vitamin D internal synthesis, and as they went to Asia they regained melanin in the South-East and even changed to another pigment in China etc - might be dual pigments. Hot climates often had ample food = over-population and competition for food = war and internecine conflict for resources and people optimised for combat. As you went North food became seasonal and people starved at time = crops/storage = less fighting = Eskimos are non combative against people, but their enemy was the climate = they learned to combat that quite intelligently with tooth/bone/sinew - also animals are high calory food, but deficiencies can lead to 'rabbit starvation' can occur, but in Eskimos was abated by fat from seals etc. https://en.wiktionary.org/wiki/rabbit_starvation So we are like cats/dogs/hamsters and the same for birds = hundreds of chicken variants. We are just meat in varied shapes/minds I recall an SF book by Jack Vance called 'Dragon Masters' where there were 2 habitable planets, one with Earth men and one with smart lizards and every few thousand years they would pass nearby and the higher tech lizards with space ships would raid the 'Earth' for slaves/plunder and would also lose some lizards to Earth capture. In the long period between orbital intersections, each side would breed their captured slaves into combat beasts of varied types. The lizards bred variants from massive Gorilla types to medium and smaller warrior variants, much like we bred cats/etc. The lizards also bred Juggers, Fiend, Blue Horror, and Murderers - all optimised for combat role against the other race. Vance created many highly creative novels, many with race variants as well as species on various planets. Often they had devolved from fallen interplanetary societies, near savagery, in a complex web of interspecies trade/conflict after the ancient fall when space travel was lost. SF in those days differed a lot from now. Even so, I found Vance's novels fascinating as a teenager. He is long gone, but not forgotten but his novels live on as e-books/audio books and are worth reading.

If there was ever a race targeting disease they will exist by definition. Those it inaccurately targets are just not pure-blooded enough.