CD8A and melanoma: Oliveira et al. also found that HLA class II positive melanomas were characterized not only by clonal expansion of Treg cells, but also by high numbers of CD8+ TILs, owing to their association with extreme TMB.1,5 The recovery of cytotoxic CD8+ responses may disrupt the delicate equilibrium between Treg and effector cells, leading to enhanced immunogenicity of HLA class II positive melanoma, which further provides a plausible immunological rationale for improving the immunotherapy of melanoma.