The definition of high-risk chronic lymphocytic leukemia (CLL) was relatively simple in the chemoimmunotherapy era, as it was defined by only one genomic marker, TP53 alteration, along with poor responses to purine-analogue based treatment. While other biomarkers such as unmutated IGHV, del(11q), high ZAP70 expression and high CD38 expression were associated with inferior prognosis, TP53 deficiency by mutation and/or del(17p) remained the only biomarker that clearly guided treatment decisions.