There are many kinds of genes tested for lung cancer in clinical practice, and it is not possible to generalize which gene test is good or bad. EGFR, ALK and ROS1 gene tests are good for positive results, because there are corresponding targeted therapeutic drugs, and even if they are negative, immunotherapy can be used. In addition, there is another kind of gene test, which is specialized in predicting targeted drug resistance. If such gene test is found to be positive, it means that it is resistant to a certain targeted drug, but it is not good. Therefore, for lung cancer, especially adenocarcinoma, genetic testing is now routinely done clinically in order to guide the patient’s medication and to be able to judge the prognosis, which is of great clinical importance.