A percutaneous biopsy on the left neck indicated a pathological diagnosis of T4N3M1c (IVB) metastatic lung adenocarcinoma....The liver metastases lesion and ctDNA were performed by NGS analysis and detected EML4-ALK fusion (level, plasma 0.24%) again, accompanied by an acquired ALK resistance mutation (ALK I1171N)...the patient then took ensartinib as the second-line treatment immediately post alectinib. Surprisingly, 20 days later, CT re-examination showed that the multiple tiny nodules in both lungs were roughly the same as before, ultrasound re-examination revealed that most of the multiple lesions in the liver were reduced compared to before...