TIGIT and non-small cell lung carcinoma: TIGIT immunohistochemical expression is currently not considered a prerequisite for the administration of TIGIT inhibitors, such as tiragolumab in non-small-cell lung cancer, for which PD-L1 positivity is deemed sufficient, and no data exist about the potential role of TIGIT expression as a predictive biomarker for response to anti-TIGIT regimens.