Metronomic gemcitabine in models of non-small-cell lung carcinoma (NSCLC) and low-dose cyclophosphamide in neuroblastoma have led to the increased efficacy and diminished toxicity of the PD-1 blockade due to reduced tumor angiogenesis dampening Tregs and enhancing the T cell effector response [57]. Here, PDCD1 is linked to non-small cell lung carcinoma.