CD19 and B-cell chronic lymphocytic leukemia: For instance, the essential immunophenotypic markers for diagnosing CLL/SLL (CD19, CD20, CD5, CD23, etc.)are the same in both WHO and ICC, and both systems recommend genomic analyses such as IGHV mutation status and TP53 deletion/mutation status for prognostication in CLL.18 This convergence underscores that the two classification frameworks are largely consistent in defining entities, even if some nomenclature differs.