DARWIN II (NCT02314481) is an exploratory phase II trial examining the role of intratumor heterogeneity and the presence of neoantigens on the efficacy of anti-PD-L1 immunotherapy in patients with epidermal growth factor receptor (EGFR)- or HER2-mutated NSCLC who have relapsed after afatinib therapy. Here, EGFR is linked to non-small cell lung carcinoma.