Each therapy has its own companion test and is only approved for cases with expression of PD-L1 above a defined threshold, using a dedicated antibody for immunolabelling (Table 3): For atezolizumab, the threshold is PD-L1 expression detected in ≥ 5% of immune cells either infiltrating the tumor or within the contiguous peritumoral stroma, using the SP142 antibody clone. Here, CD274 is linked to neoplasm.