Don’t know what you mean about being “directly linked to Rhesus” monkeys. Rh factor refers to a type of protein — and there are many others — that is found on the surface of RBCs. The “Rh” part was used to name it because of the fact that the rhesus monkey was used in lab work to identify this factor.
Most people are Rh positive. The only time one needs to be concerned about this factor is in pregnancy. If a mother is Rh negative and her unborn baby is positive, the mother’s immune system might attack the fetus as a foreign body.