CD274 and non-small cell lung carcinoma: BIRCH was a phase II, single-arm study that administered atezolizumab in the first- (cohort 1), second- (cohort 2), and third-line (cohort 3) settings in the treatment of advanced NSCLC in patients with a minimum of 5% PDL-1 expression on both tumor cells (TC2/3) and tumor-infiltrating immune cells (IC23), as determined by immunohistochemistry.