Intriguingly, when analyzing the immunotherapeutic response in a cohort of GSE78220 and IMvigor210, the response group proved the lower MRC2 expression level in metastatic melanoma with pembrolizumab (p = 0.071, Figure 5D) and advanced urothelial cancer with atezolizumab (p = 0.0046, Figure 5E). Here, MRC2 is linked to metastatic melanoma.