We modeled the drug-sensitive (DS), drug-tolerant (DT), and drug-resistant (DR) continuum by using the clinically approved EGFR inhibitor erlotinib to treat a well-studied EGFR-mutant lung cancer cell line PC9, which was subjected to ATAC-seq and RNA-seq in parallel (Fig. 1A). Here, EGFR is linked to lung carcinoma.