PDCD1LG2 and melanoma: Meanwhile, several studies found that PD-L2 expression was an independent prognostic factor associated with a good prognosis in oropharyngeal squamous cell carcinoma (Danilova et al. 2016; Obeid et al. 2016; Steuer et al. 2018) and melanoma (Danilova et al. 2016; Obeid et al. 2016; Steuer et al. 2018) patients.