CD274 and laryngotracheoesophageal cleft: Immune checkpoint proteins including the programmed cell death protein 1 (PD-1/PDCD1), programmed death-ligand-1 (PD-L1/CD274), and cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) are established prognostic markers for LC patients (Cariani and Missale, 2019; El Dika et al., 2019; Johnston and Khakoo, 2019).