In addition to the genomic alterations, previous studies also revealed the presence of programmed cell death protein ligand 1 (PD-L1) and CD8-positive tumor-infiltrating lymphocytes (TILs) to be associated with a worse clinical outcome in epidermal growth factor receptor (EGFR) mutated NSCLC patients, receiving an EGFR inhibitor [9], indicating that the immunological composition of the tumor microenvironment (TME) could play a role in the response to tyrosine kinase inhibitors. The gene discussed is CD8A; the disease is non-small cell lung carcinoma.