According to this classification, the CLL microenvironment should be classified as type II, thus explaining the relatively poor results obtained with therapies based on PD-1 blockade, whereas the RS microenvironment might fit into a type I definition, therefore justifying the more favorable outcomes of PD-1/PD-L1 inhibition [69,75]. Here, CD274 is linked to B-cell chronic lymphocytic leukemia.