The study is designed to compare the efficacy of asciminib 80 mg QD versus Investigator selected Tyrosine Kinase Inhibitor (TKI) for the treatment of newly diagnosed, previously untreated patients with Ph+ CML-CP. The Investigator selected TKI will be one of the following treatment options for first-line treatment of CML-CP - imatinib 400 mg QD or nilotinib 300 mg BID or dasatinib 100 mg QD or bosutinib 400 mg QD. This study has three periods: 1. Treatment period for all randomized participants, 2. Optional Treatment-Free Remission (TFR) period only for participants meeting TFR eligibility criteria and 3. Treatment Re-Initiation (TRI) period only for participants who relapsed after TFR attempt.