Uryvaev and colleagues observed that patients with a ratio of CD8+/CD4+ in TME lower than 2 had a response rate of 13.3% (p: 0.046) in metastatic NSCLC treated with anti-PD-1, whereas if it is higher than 2, the response rate ascends to 43–50% (p: 0.038). Here, CD4 is linked to non-small cell lung carcinoma.