Microenvironment composition as assessed by IHC staining. (A) Box plots represent the percentage of nucleated cells that are positive for each given marker (P values calculated with Student t tests). T-cell subsets were analyzed by using CD3, CD4, CD8, FOXP3, PD1, and LAG-3. Macrophage subsets were identified by using CD68 and CD163. (B) Representative images of cHL, thymic bona fide GZL (ie, groups 1 and 2 with thymic involvement), and PMBCL tissue stains. Original magnification at 400× for all images. **P ≤ 0.01; ***P ≤ .001; ****P ≤ .0001. H&E, hematoxylin and eosin; ns, not significant (P > .05).