@liz8716- Good morning. This must be very scary and confusing for you. Many people, including myself have wondered what questions to ask. One thing I will encourage you to do is to get a second and maybe 3rd opinion. Get copies of all of your blood work, treatments and chemo infusions. I don't think that you have told us what kind of lung cancer you have. Different types of cancers work better than others with Keytruda but it is showing a lot of promise and research is extremely strong for lung cancer. There have been a lot of improvements in this area with new drugs and new treatments.
When I got my first cancer 5 years also looked like it was unreachable. But it's there. And it's hard not to think about it. And it's almost impossible to think about nothing else!
I have had both chemo and SBRT. I had navelbine and cisplatin. That was awful. I had chemo twice a week for 4 months. SBRT is:Stereotactic radiation therapy. Stereotactic radiation therapy, also called stereotactic external-beam radiation therapy and stereotaxic radiation therapy, is a type of external radiation therapy that uses special equipment to position the patient and precisely deliver radiation to a tumor. (Wikipedia).
Do you have more than one major hospital in your area? Are you healthy enough to travel to seek a second opinion?