Timeline for the discovery of BTK highlighting key milestones in BTK‐related research and therapies. Each section represents a decade. Ac, acalabrutinib; CLL, chronic lymphocytic leukaemia; GVHD, graft‐versus‐host disease; Ib, ibrutinib; MCL, mantle cell lymphoma; MZL, marginal zone lymphoma; WM, Waldenström's macroglobulinaemia; XID, X‐linked immunodeficiency; XLA, X‐linked agammaglobulinaemia