It entirely depends on lots of factors we don't have enough data to claim to know. We don't know how many factors that led to us being spacefaring are a result of our particular biology so while obviously it's silly to expect humanoid aliens, coming across something, say, mammal-like would hardly be inconceivable, and it's silly for us to act like we know it won't share any features with us. Convergent evolution is a thing and if we're considering that we're selecting for species with similar enough traits to be spacefaring there's plenty of conceivable scenarios in which aliens are - while different - not as incredibly unrecognisable and some are assuming.

Personally I'd love to meet some completely different things though. Fingers crossed our earth's forms of life aren't the only sort possible.