This is the 2365th most frequent Turkish word.
gelebilir
"Can come" or "might come."
Here 'gelebilir' is showing possibility, indicating that Ali might join the event.
Bugün Ali bizimle sinemaya gelebilir.
Ali might join us for the cinema today.
In this case, 'gelebilir' is showing an ability or capability that the subject (you) can attend.
Belki yarın toplantıya gelebilirsin.
Perhaps you can attend the meeting tomorrow.
Here 'gelebilir' is used to show conditional ability, depending on the weather.