Preoperative Radioimmunotherapy Versus Chemoimmunotherapy in NSCLC

The goal of this clinical trial is to learn if Cemiplimab with chemotherapy or Cemiplimab with stereotactic body radiation therapy (SBRT) works as treatment for stages IB, II, and III (N2) Non-Small Cell Lung Cancer (NSCLC). Before surgery to remove their lung cancer, participants will take: 1. Cemiplimab with chemotherapy (Arm A) every 3 weeks for up to 3 doses, OR 2. Cemiplimab every 3 weeks for up to 3 doses with SBRT (Arm B). SBRT will be given on day 1 before taking cemiplimab, then SBRT alone on day 2 and day 3. Four to 12 weeks following surgery, participants in both Arm A and Arm B will receive treatment with cemiplimab for one year.