In 2023, a pan-cancer immunotherapy response study built a predictive model based on endothelial senescence and showed that the machine learning algorithm “KKNN” had the highest AUC for response at 0.75 in the anti-PD-1/PD-L1 treated melanoma cohort (PUCH SKCM, 2021), while in other melanoma immunotherapy cohorts the AUC decreased to around 0.5, and the AUC for OS was even lower (32). Here, PDCD1 is linked to melanoma.