Research suggests that miR-340-5p plays a role in regulating PD-L1 and may be associated with the response to pembrolizumab in extranodal NK/T-cell lymphoma. Similar microRNAs have been studied in other types of cancer, including non-small cell lung cancer and cervical cancer, where they have been found to have prognostic value or be involved in oncogenic pathways. The specific relationship between miR-340-5p and pembrolizumab response in extranodal NK/T-cell lymphoma is the focus of the current study.