My dad was diagnosed with Stage 4 NSCLC adenocarcinoma with metastasis to the lymph nodes in the chest and neck and on one of the vertebrae on the 5th of October 2021. He's only 49(never smoked). He had symptoms such as being out of breath, coughing up blood, sometimes uncontrollable coughing to the point in which he vomits, hoarse voice, fatigue and weight loss. He's had no body pain anywhere thank god.He started treatment in November with chemo-based drugs carboplatin and pemetrexed with keytruda immunotherapy. His side effects after treatments were initially quite bad and he was hospitalised a few times but his last 2 treatments his side effects were very minuscule. It's now mid January and he's feeling really good - absolutely no to little symptoms touchwood only some breathlessness with a very minor cough and no hemoptysis. He's also regained so much more weight after he lost a large amount. Is this a sign the treatment is working because he's suddenly now full of energy and feeling good and is even leaving the house more often. I've read that some people have been completely cured of stage 4 nsclc after immunotherapy use - could this be the case if he continues on the same track?