To understand the effect of knockout of S100A9 in hematopoietic cells on the pro‐fibrotic immune cell‐stromal crosstalk in JAK2V617F‐induced MPN, and to compare the results to the treatment with tasquinimod, we performed single‐cell RNA sequencing (scRNAseq;10x Genomics platform). Here, S100A9 is linked to myeloproliferative disorder.