The lore before this suggested that they weren't really that close, and the two had opposing views from the start, especially when Orion was made a Prime, and Megatron was not. Transformers One ...

The recently published lore comic provides some context for this crossover, too: Megatron has arrived in the world of Overwatch 2 and intends to claim it for the Decepticons. To do so, he enlists ...