My Wife Has Stage IV Lung Cancer And Has Had

My wife has Stage IV lung cancer and has had part of her lung removed. She went through chemo then to Xalkori and finally she is on Alectinib (Aelcensa). She has never smoked and does possess the ALK gene. Her recent CT scan (5 days ago) shows a new 3mm right upper lobe pulmonary nodule somewhat non specific. What does that mean? Thank you.