Therefore, our aim consisted of evaluating the predictive roles of pre-SABR CD8+ T-cell counts, CD8+CD28+ T-cell counts, CD8+CD28− T-cell counts, CD4+ T-cell counts, and Treg-cell counts in peripheral blood for early tumor response to SABR in patients with lung metastases from NSCLC. The gene discussed is CD28; the disease is non-small cell lung carcinoma.