What are the major crossover events in gta online?

The provided source discusses internet leaks but contains no information about GTA Online or any crossover events within that game. Because the evidence does not cover this topic, we cannot confirm the existence or details of any crossover events. It is possible that such events exist, but without verified sources we cannot provide specifics. Therefore, we recommend consulting official Rockstar Games releases or reputable gaming news outlets for accurate details on GTA Online crossovers.