We can't tell from the pictured symptoms what originally caused the damage, but the trunk injury that is resulting in bark cracking might have caused dieback for some branches or parts of the canopy. A canker disease is possible, but not the only explanation for a zone of dead trunk tissue. When they do occur, canker infections tend to take advantage of weakened trees that are under stress, even if they don't look stressed.

It will only become apparent if damage is widespread once the tree leafs-out in several more weeks. Make sure the tie is either removed (if it was put on last year sometime) or at least loosened to allow the trunk to sway in the breeze by several inches in any direction. If staked too tightly, not only can the tie itself injure the bark, but the restriction on movement won't allow the roots to anchor the tree as well.

There is nothing you can do about the trunk crack or flaking bark right now, so just monitor the tree for indications of dieback over the next month or two. Branches that do not leaf-out by the time the rest have leaves fully expanded can be pruned off because they will not recover. (If no foliage appears by mid-May or so when other trees in the area have leaves, the redbud may have died or will be so weak it should be replaced.) Check the trunk base to ensure the bark is not covered by mulch (which should only be in a 2- to 3-inch layer) and the root flare (where roots branch off of the trunk) should be just visible at the soil surface. If it's buried by several inches, that can hamper establishment or threaten the health of the tree for the long term, so gently expose it by moving aside any surplus soil covering it up if it was planted too deeply originally.

Miri