Is there a reason why Bob (the soldier that appeared in the first Deadpool movie working for Ajax) didn't make an appearance in Deadpool 2?
Do we even know if he survived in first film?
As per Wikipedia:
It is unknown if he survived Negasonic Teenage Warhead's last burst that caused the hull to roll over on top of the fire fight and everything in the immediate area
To be frank it feel like just an Easter egg where we don't need to dig more. And member Bob was Bob, Agent of Hydra in comics and Fox doesn't have rights of using Hydra. So they can't even play with the character's comicbook part much yet but nobody know about future.
Bob's absence and Peter's inclusion also make the speculation that maybe Peter's is Fox's answer to Bob.