Bard is a support champion that can put multiple units including towers into stasis, you can use this both offensively and defensively, and is actually a great mechanic during team fights.
Putting a character into stasis stops everything for them including movement, channeling, and even health and mana restorations. Nothing and nobody can touch you while you are in stasis and this is a form of a hard CC meaning it completely immobilizes you and prevents you from taking any action.
Cleanse is an active item effect or a summoner spell that can dispel any immobilizing effect on a champion. Cleanse also removes almost all types of debuffs in a champion and with Bard’s ultimate putting units into stasis, can you really cleanse Bard’s ultimate?
The answer is no and here is why, when you are in stasis, that status prevents you from taking any action, meaning all summoner spells and active item effects are disabled. External effects will also not reach the champion in stasis meaning the cleanse from Mikael’s active effects won’t affect a champion in stasis.
Even targeted summoner spells like exhaust or ignite won’t take effect as the champion becomes untargetable. AoE effects are also ineffective to champions under stasis like heal or Redemption’s active item effect.
There is a way however to prevent yourself from being affected by stasis, there are active spells that block magic damage or any immobilizing effects like Nocturne’s and Sivir’s spell shields. Cast it at the perfect time just before Bard’s ultimate hits the ground and you will not be put under stasis.