Corbyn tabled a Vote of No Confidence. However, this isn’t the VoNC we were hoping for. That would be a VoNC in the government, this is a VoNC in the PM herself, and is thus non-binding and does not lead to any direct consequences.
However, the past precedence has been that a PM resigns if they lose a VoNC in themselves. As for when this would take place, well, the Government could simply not allow it to take place at all, which would look terrible, but losing it would look even more terrible, so who really knows?