CD4 and cancer: We created two candidate measures: TN/ (TCM + TEM + TEFF) (referred as TN/ TM) in CD4 + and CD8 + T cells and benchmarked them against CD4/CD8 ratio, CD8 + TN and CD4 + TN by evaluating associations of all these measures with chronological age, biological age, multimorbidity (that includes several aging-related diseases such as diabetes, cancer, lung disease, stroke, and heart disease), and mortality.