LAG3 and neoplasm: Likewise, despite multiple studies identifying LAG-3 in MPM tumors and pleural effusions,30 40 it is generally less commonly expressed than other inhibitory receptors, particularly within the tumor,21 41 and a detailed examination of CTL immune checkpoints revealed that LAG-3 tended to be a companion to PD-1 rather than a solo exhaustion marker.42 Hence, an anti-LAG-3 therapeutic strategy for CTLs may not be favored at present but merits further investigation.