Sieviläinen M, et al. - Authors conducted a systematic review to investigate the prognostic significance of immune checkpoints in oral squamous cell carcinoma (OSCC). A systematic search was conducted in Ovid Medline, Scopus and Cochrane libraries and all studies that evaluated the prognostic significance of immune checkpoints in OSCC. Despite high expectations for OSCC prognostication via immune checkpoint markers, the majority of them had been studied only once. Findings were controversial for the other molecules, which had been studied more than once, except B7-H3. There were also controversial findings in the results for PD-L1, as it was reported to be correlated to both better and worse patients′ survival.