Preoperative Radioimmunotherapy Versus Chemoimmunotherapy in NSCLC

Inclusion Criteria: 1. Patients with histologically or cytologically proven clinical stages IB (T2aN0), II, and III(N2) NSCLC (according to AJCC version 9) eligible for surgical resection with curative intent. Patients with 2 synchronous NSCLC are allowed. 2. Measurable disease, as defined by RECIST v1.1. 3. Known PD-L1 expression. 4. No known EGFR mutations or ALK fusions. 5. Written informed consent and HIPAA obtained from the subject prior to performing any protocol-related procedures. 6. Age \> 18 years at time of study entry. 7. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. 8. No prior therapy for lung cancer 9. Adequate organ and bone marrow function as defined below: • Absolute neutrophil count (ANC) ≥1.5 x10(3)/uL • Platelets ≥75 x10(3)/uL • Hemoglobin ≥9 g/dL • Serum creatinine ≤1.5 X upper limit of normal (ULN) OR calculated CrCl ≥50 ml/min (using the Cockcroft-Gault formula). * Serum total bilirubin ≤1.5 X ULN, except in patients with clinically documented Gilbert's Syndrome where ≤3x the ULN is permitted * Aspartate aminotransferase (AST)/ Alanine aminotransferase (ALT) ≤3 X ULN 10. WOCBP\* must have a negative serum (beta-hCG) at screening. a) \*WOCBP are defined as women who are fertile following menarche until becoming postmenopausal, unless permanently sterile. Permanent sterilization methods include hysterectomy, bilateral salpingectomy, and bilateral oophorectomy. \- A postmenopausal state is defined as no menses for 12 months without an alternative medical cause. A high FSH level in the postmenopausal range may be used to confirm a postmenopausal state in women not using hormonal contraception or hormonal replacement therapy. However, in the absence of 12 months of amenorrhea, a single FSH measurement is insufficient to determine the occurrence of a postmenopausal state. The above definitions are according to the CTFG guidance. Pregnancy testing and contraception are not required for women who are post-menopausal or with documented permanent sterilization. b) Male study patients with WOCBP partners are required to use condoms unless they are vasectomized or practice sexual abstinence. c) Vasectomized partner or vasectomized study patient must have received medical assessment of the surgical success. d) Periodic abstinence (calendar, symptothermal, post-ovulation methods), withdrawal (coitus interruptus), spermicides only, and LAM are not acceptable methods of contraception. Female condom and male condom should not be used together. 11. WOCBP must agree not to donate eggs (ova, oocytes) for the purposes of assisted reproduction during the entire trial and until 6 months after last treatment. 12. All men must agree not to donate sperm during the trial and for 6 months after receiving the last therapy dose. Exclusion Criteria: \- 1. History of another primary malignancy except for: -Malignancy treated with curative intent and with no known active disease ≥2 years before the first dose of the study drug and of low potential risk for recurrence. -Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease. * Adequately treated carcinoma in situ without evidence of disease e.g., cervical cancer in situ, in-situ urinary bladder cancer, treated localized prostate cancer, and ductal carcinoma in-situ. * Indolent hematological malignancies 2. Current or prior use of immunosuppressive medication within 14 days before the first dose of cemiplimab, with the exceptions of intranasal, inhaled, topical steroids, or local steroid injections (e.g.intra articular injection), corticosteroids or systemic corticosteroids at physiological doses which are not to exceed 10 mg/day of prednisone or an equivalent corticosteroid, and steroids as premedication for hypersensitivity reactions (e.g., CT scan premedication). 2.a. Any condition that requires ongoing/continuous corticosteroid therapy (\>10mg prednisone/day or anti-inflammatory equivalent) within 1 week prior to the first dose of study medication. Participants who require a brief course of steroids (up to 2 days in the week before enrollment) or physiologic replacement are not excluded. 3\. Active or prior documented autoimmune or inflammatory disorders (including inflammatory bowel disease \[e.g., colitis or Crohn's disease systemic lupus erythematosus, sarcoidosis syndrome, or Wegener syndrome \[granulomatosis with polyangiitis, Graves' disease, rheumatoid arthritis, hypophysitis, uveitis, etc\]. No active diverticulitis within the previous 3 months. The following are exceptions to this criterion: * Patients with vitiligo or alopecia * Patients with endocrinopathies (such as hypothyroidism or type 1 diabetes (e.g., following Hashimoto syndrome) stable on hormone replacement, or psoriasis that does not require systemic treatment. * Any chronic skin condition that does not require systemic therapy * Patients with childhood asthma that has resolved 4. Uncontrolled, intercurrent illness including, but not limited to: ongoing or active infection requiring antibiotics (exception is a brief (≤10 days) course of antibiotics to be completed before initiation of treatment), symptomatic congestive heart failure, unstable angina pectoris, or psychiatric illness/social situations that would limit compliance with study requirements as determined by the Investigator. 5\. Interstitial lung disease (eg, idiopathic pulmonary fibrosis, organizing pneumonia) or active, noninfectious pneumonitis that requires immune-suppressive doses of glucocorticoids to assist with management. A history of radiation pneumonitis in the radiation field is permitted as long as pneumonitis is resolved ≥6 months prior to study treatment. 6\. Receipt of a live vaccine within 30 days of the planned start of study medication. Note: If a patient intends to receive a COVID-19 vaccine before the start of the study drug, participation in the study should be d