Abstract: A method of immune phenotyping (evaluating adaptive and innate immune status) a subject is disclosed that includes providing a biological sample comprising diluted whole blood or isolated peripheral blood mononuclear cells (PBMCs), quantitating T cell interferon-gamma (IFN-?) and monocyte TNF-? production using ELISpot in the biological sample comprising diluted whole blood, and determining that the subject has an immunosuppressive immunological endotype if T cell interferon-gamma (IFN-?) and/or monocyte TNF-? production are decreased or low compared to a healthy subject. The disclosed method may be used to evaluating drug efficacy by measuring immune function in a subject after administering a drug to the subject to determine changes in the immune function of the subject in response to the drug.