In fact, in clinical trials on pembrolizumab and nivolumab, the predictive potential of PD-L1 expression has been based on its evaluation on tumor cells only using the tumor proportion score (TPS)/tumor cells (TCs), which is defined as the percentage of PD-L1-positive tumor cells (partial or complete) relative to the total number of viable tumor cells [65,66]. The gene discussed is CD274; the disease is neoplasm.