Does damage assigned by a creature with trample carry over to the defending player if the blocking creature has indestructible?

Trample (CR 702.19) lets a creature assign combat damage to the defending player (or planeswalker) as long as each blocking creature has been assigned at least lethal damage first. Lethal damage is defined in CR 702.19b as damage greater than or equal to the blocker's toughness, accounting for damage already marked on it.

Indestructible (CR 702.12) means the creature cannot be destroyed by damage or by effects that say 'destroy.' Crucially, indestructible does not change what counts as lethal damage for trample purposes. CR 702.19b explicitly states that for an indestructible creature, lethal damage is still damage equal to its toughness — the attacker must assign that much, but no more is required.

So if you attack with a 10/10 trampler and it is blocked by a 2/2 indestructible creature, you must assign at least 2 damage to the blocker. The remaining 8 damage tramples through to the defending player. The 2/2 survives because it is indestructible, but the player still takes 8.

This interaction is confirmed by CR 702.19b: 'Lethal damage is the amount of damage that would be sufficient to destroy [the creature] if it were not indestructible — that is, damage greater than or equal to its toughness.' The assignment rule does not protect the player just because the blocker won't die.

In short: indestructible blockers soak the minimum lethal assignment, but they do not act as a perfect shield against a trampling attacker. Excess damage still carries over.