Notably, although PD-L1 has shown important utility as a predictive biomarker in some tumor types, some patients with high levels of PD-L1 expression do not respond well to anti-PD-1 therapy, while some patients with a lack of PD-L1 expression actually do better, suggesting that apart from PD-L1, other receptors that interact with PD-1 molecules, such as PD-L2, and other factors may be involved in the response to ICIs (Yearley et al., 2017; Li et al., 2020). Here, PDCD1LG2 is linked to neoplasm.