Additionally, Yang et al. uncovered the potential role of USP21 in immune escape due to the mechanism of USP21-mediated PD-L1 stabilization, and suggested the positive correlation between USP21 and PD-L1 in lung cancer, especially in lung squamous cell carcinoma, a main subtype of NSCLC (Yang et al., 2021). This evidence concerns the gene USP21 and squamous cell lung carcinoma.