CTLA4 and melanoma: Notably, they showed that CTLA4 and PD-L1 blockades activate non-redundant mechanisms in the melanoma of mice receiving photon radiotherapy: CTLA4 blockade decreases and increases the proportion of Treg and CD8+ T cells in tumor-infiltrating lymphocytes, respectively, but simultaneously induces exhaustion in CD8+ tumor-infiltrating lymphocytes via inducing PD-L1 expression on cancer, while PD-L1 blockade reinvigorates these exhausted CD8+ T cells.