Insights into CLL afforded by single-cell analysis. (A) Schematic of a typical CLL disease course and conceptualization of the coevolution with host immunity. Thus far, single-cell analysis has been applied to evaluate the molecular features intrinsic to CLL cells at baseline (B) as well as after therapy (C). Likewise, single-cell analysis has been applied to evaluate the native state of the CLL immune microenvironment (D) as well as the dynamic changes in immune cell populations after immune therapies (E). WBC, white blood cell.