Introduction:Immunotherapy is the main oncological treatment for mNSCLC for which the discovery of new efficient biomarkers is crucial. Scientific evidence points to the importance of the Lung Immune Prognostic Index (LIPI), but its predictive significance is unclear.Aim:The aim of this study was to investigate the clinical significance and predictive role of LIPI in patients with mNSCLC and PD-L1 mutation who are eligible for immunotherapy in combination with chemotherapy and association between COVID-19 infection and the course and outcome of oncologic treatment of NSCLC has been investigated.Patients and Methods:Patients were divided into four study. LIPI was determined and its predictive power was evaluated in all studied groups, as well as overall survival (OS), progression-free survival (PFS), and disease control rate (DCR). Results:This study confirmed the understudied and uncertain predictive power and clinical relevance of LIPI as a biomarker in patients with mNSCLC. Patients infected with COVID-19 had a higher survival rate than uninfected patients.Conclusions:Findings obtained in this study may help to determine treatment options according to the clinical condition of the patient by using LIPI values as a non-invasive, readily available and economically acceptable predictive biomarker in lung oncology.