This figure shows images of specimens stained with hematoxylin and eosin. There are 4 images of primary tumor on the left and 4 images of metastatic lymph node on the right. The top row contains four images, and the bottom row contains another four images. These images are from a representative P-RAD patient who was treated either with anti-PD1 alone or Radiation therapy and anti-PD1. The top row features images taken with anti-PD1 alone. With two images corresponding to baseline and two images from week 2.5. One of the week 2.5 images show the treatment with anti-PD1 only and while the other shows the combination of Radiation Therapy and anti-PD1.