Treatment with trametinib alone leads to the up-regulation of major histocompatibility complex (MHC-I) and PD-L1 on tumor cells in vitro, and it has been suggested that the combination of trametinib with anti-PD-1 drugs can lead to enhanced cytotoxicity of hepatic effector memory CD4 + T cells, reduced tumor burden, and improved survival in tumor-bearing mice 54. Here, PDCD1 is linked to neoplasm.