My professor said that control variables are generally thought to be exogenous in an OLS context, i.e. uncorrelated with the main independent variable in my regression. However, I think that they are endogenous and not only determine the dependent variable but also correlate with the independent variable of my interest. So, my question: Should we think of control variables as being exogenous to the independent variable of our interest in our OLS regression? If so, how do we call an endogenous "control variable"? Maybe it's just terminology that's confusing me.