The current standard method to determine PD-L1 expression is the visual analysis of immunohistochemically (IHC) stained whole slide images (WSIs) by trained pathologists to estimate the PD-L1 expression tumor proportion score (TPS).14, 15, 16, 17 Pathologists have limited time to evaluate a tumor and therefore cannot assess the PD-L1 status of each cancer cell individually. The gene discussed is CD274; the disease is cancer.