Immunoscore (R) is a digital pathology diagnostic immunoassay used to complement tumor node metastasis staging for the prediction of recurrence risk in patients with early-stage colon cancer. In combination with standard clinicopathological features, Immunoscore (R) informs adjuvant chemotherapy decision-making for patients with early-stage colon cancer. Immunoscore (R) has been validated in patients with stage II/III colon cancer and demonstrated to be a stronger prognostic factor for survival than tumor node metastasis staging alone. Immunoscore (R) improves the prognostic definition of patients with colon cancer, the identification of those patients at high risk of tumor recurrence, and the ability to predict which patients will derive most benefit from the use of adjuvant chemotherapy. Immunoscore (R) has robust analytical performance characteristics which include good interlaboratory reproducibility and overall assay precision.