Previous studies [22,23,24,25,26,27] revealed that the expression status of PD-1/PD-L1 in tumor cells is associated with the treatment outcomes, and methods toward the noninvasive identification of PD-1-positive tumors have also been investigated by using imaging features or radiomic feature-based contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI). This evidence concerns the gene PDCD1 and neoplasm.