Unanswered questions: immunotherapy for lung cancer

I'm on the end of my Chemo & Radiation treatment for small cell lung cancer. My cancer doctor mentioned a one year autoimmune therapy but refused to answer any questions about it until the time comes. To the point that he yelled at me for asking the questions. I am so confused and frustrated. This entire cancer experience is new to me and even though I requested all my risks, systems, procedures, everything explained to me in the very beginning, I learned quickly, my requests were ignored. I'm seeing the top cancer doctors in my area. But, I'm looking at making a decision on to live or die. Please, any information will be greatly appreciated.