Background: The National Comprehensive Cancer Network (NCCN) currently recommends the use of Atezolizumab, Nivolumab, Osimertinib, and Pembrolizumab in the perioperative management of non-small cell lung cancers (NSCLC) and esophageal cancers (EC). As the therapeutic landscape evolves, we aim to evaluate the cost implications of these guidelines for eligible patients in the United States. Methods: The Medicare Part B payment allowance limits of each medication were ascertained except Osimertinib for which an approximate wholesale acquisition cost (WAC) was reported due to privately administered Medicare Part D coverage. Using national data and published literature, we estimated the annual incidence of patients with newly diagnosed EC and NSCLC who would be eligible for surgery combined with neoadjuvant and/or adjuvant immune and targeted therapy. We applied the estimated cost of the medication based on dosing and duration of treatment, which spanned 1 year for all but adjuvant Osimertinib, which spanned 3 years. Using these data, the cost per patient and the total cost for an incident cohort were estimated. Results: We estimated that 8,602 patients with newly diagnosed EC would be eligible for adjuvant Nivolumab; the cost to treat one patient was $248,529, and the cost to treat one incident cohort was approximately $2 billion (Table). We estimated that 50,409 patients with NSCLC will meet the criteria for neoadjuvant Nivolumab with a total cost of three cycles of $32,894 per patient and $1.7 billion per cohort. Among NSCLC patients who may undergo resection and qualify for adjuvant therapy (Stage IB – IIA with high-risk features or IIB-IIIA), 85,063 patients are anticipated to be EGFR-negative and treated with adjuvant Atezolizumab or Pembrolizumab. Treatment costs range from $178,584 – $197,320 per patient with up to $16 billion cost per cohort. The cost to treat one patient with adjuvant Osimertinib was $556,720, and the cost to treat one incident cohort was close to $10 billion. In total, the cost to treat an incident cohort of eligible operable thoracic malignancies could exceed $30 billion. Conclusions: Neoadjuvant and adjuvant immune and targeted therapy in operable thoracic patients is associated with a significant cost burden. Prospective large-scale studies are needed to assess cost-effectiveness, particularly given the paucity of superior overall survival data with these agents.