This is a non-randomized, prospective, single-group longitudinal study. The overall objective is to improve decision making for TKI discontinuation in eligible chronic myelogenous leukemia (CML) patients. Patients with CML on treatment with imatinib, dasatinib, nilotinib, or bosutinib and are in confirmed deep molecular response will stop their TKI. Confirmed deep (> 4 log reduction) molecular response (>MR4) defined as p210 (bcr-abl) fusion protein (BCR-ABL) < 0.01%, for at least two years. The study will closely monitor patients using standard real-time Quantitative Polymerase Chain Reaction (RQ-PCR) testing for molecular recurrence, testing them monthly for six months, then every other month until 24 months, and then quarterly until 36 months. Concurrently, the study will assess a wide range of patient-reported outcomes (PROs) before stopping TKIs and after discontinuation in conjunction with Polymerase Chain Reaction (PCR) testing, though at fewer time points, utilizing online and/or phone questionnaires. Patients who have molecular CML recurrence based on RQ-PCR will restart imatinib, dasatinib, nilotinib, or bosutinib and will continue to be monitored for disease status and health status until the end of the study.