CD274 and non-small cell lung carcinoma: In the B-F1RST trial (NCT02848651), the potential of blood-based tumor mutational burden (bTMB), assessed using the FoundationOne Liquid CDx assay, was prospectively evaluated as a predictive biomarker for first-line atezolizumab in advanced NSCLC patients unselected for PD-L1 status.