CD274 and cervical squamous intraepithelial neoplasia: A previous study found a direct correlation between PD-L1 and PD-1 expression levels, cervical intraepithelial neoplasia (CIN) grade, and HPV positivity rate, implying that the PD-1/PD-L1 pathway could impair cervical immunity in CIN-related high-risk human papillomavirus (hr-HPV) (9).