Chikyuu Tansa Houkoku Loneliness

This science fiction human drama is centered on an alien living in Ikebukuro, assigned to explore the Earth. Unable to understand its people, whose only concerns are “money” and “sex,” the alien is on the verge of losing his confidence as a member of a xenoprobe team when one day he meets a man who calls himself “Honda,” an Earth name. The alien begins to respect Honda, who guides him around town as a “space senior"...

(Source: Natalie, tranlated)

Published in the Comic Beam in the late 90s, it was releassed in tankoubon format 20 years laters in 2018.