ABSTRACT
Brain metastases are the major cause of adult malignant nervous system tumors. For this part of population, treatment options are limited and the prognosis is poor. In recent years, immunotherapy based on inhibitors of programmed cell death protein 1 (PD-1) and programmed cell death receptor ligand 1 (PD-L1), have brought innovation to the treatment of malignant tumors. Immune checkpoint inhibitors (ICIs) have revolutionized the management of advanced non-small cell lung cancer (NSCLC). Encouraging results have suggested that ICIs could be active in selected advanced NSCLC brain metastases with driver-negative patients. However, for patients with brain metastases, not only the corresponding clinical data are limited, but also the evaluation of its efficacy lacks a unified standard. This article aims to review the relevant efficacy evaluation standards and their application in clinical researches, compare the similarities and differences, and look forward to future trends. .