Bruton tyrosine kinase inhibitors (BTKis) and BCL2 inhibitor (BCL2i)–containing regimens significantly improve survival outcomes in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Results from randomized clinical trials have demonstrated that time-limited treatment with BCL2i-containing regimens resulted in higher rates of undetectable measurable residual disease (uMRD) than BTKi monotherapy or chemoimmunotherapy (CIT). Pirtobrutinib (a noncovalent BTKi) and lisocabtagene maraleucel (CD19-directed CAR T-cell therapy) are newer options for relapsed or refractory disease after prior therapy with BTKi and BCL2i-contining regimens. Histologic transformation of CLL/SLL to diffuse large B-cell lymphoma (Richter transformation) is associated with a poor prognosis. Molecular analysis to determine whether there is clonal relationship between CLL/SLL and transformed diffuse large B-cell lymphoma is useful to select an appropriate treatment option. These NCCN Guideline Insights highlight significant updates to the NCCN Guidelines for the treatment of CLL/SLL and Richter transformation.