In this review, we highlight the current knowledge about TIGIT as a molecular target for lung cancer treatment across all current clinical trials employing anti-TIGIT mAbs; furthermore, we examine the role of TIGIT as a prognostic and predictive biomarker in human cancer, with a focus on immunohistochemistry and its possible prognostic, predictive, and overall theranostic applications on lung cancer. The gene discussed is TIGIT; the disease is lung carcinoma.