Guest host: Mo Rocca. David Martin examines why Russia's tank war has stalled, while Lee Cowan looks at the plight of millions of Ukrainian refugees. Plus: Tracy Smith sits down with actress Sandra Bullock; Erin Moriarty talks with former college classmates of Supreme Court nominee Ketanji Brown Jackson; Mo Rocca goes behind the scenes of the creation of the classic musical "Sunday in the Park with George"; David Pogue gets at the cause of rising gas prices; Susan Spencer looks into the mental health crisis caused by the COVID pandemic; and John Dickerson explores the importance of practice from acclaimed classical pianist Jeremy Denk.