In Phase A, participants will receive unique doses and schedules of oral ABBV-744 pill to recognize safe dosing regimen. More participants is going to be enrolled within the recognized monotherapy dosign program. In Segment B, individuals will obtain oral ruxolitinib and ABBV-744 are going to be provided as "insert-on" therapy. https://abbv-744combinationtherap46891.ampedpages.com/5-easy-facts-about-is-abbv-744-effective-for-hematologic-cancers-described-59128633