[@rush99999] I used a methane breather as an example, but any alien race will likely have completely different biochemistry. As a result they don't compete for the same worlds, they can't eat the same foods or use the same medicines, they probably need full life support rigs to even visit each other. Under these circumstances trade and war are pointless so there aren't a lot of reasons to interact. There might be some tourism but probably not a tremendous amount.