Furthermore, under the current guideline, the results of PD-L1 expression are not necessary when considering anti–PD-1/PD-L1 therapy (Bukhari et al., 2018), and tumor mutation burden (TMB) and microsatellite instability (MSI-H) are also potential predictors associated with immunotherapy outcomes in melanoma and non–small-cell lung cancer (NSCLC) (Arora et al., 2019). This evidence concerns the gene PDCD1 and melanoma.