Question: What musical profession did Milo Aukerman and Koshi Inaba have in common?

Context paragraphs:
Cool to Be You: Cool to Be You is the sixth studio album by the American punk rock band the Descendents, released in 2004 through Fat Wreck Chords.  It was their first album of new studio material since 1996's "Everything Sucks", which had been released through Epitaph Records.  Following "Everything Sucks", singer Milo Aukerman had returned to his biochemistry career while the other members—bassist Karl Alvarez, guitarist Stephen Egerton, and drummer Bill Stevenson—had continued with their other band All, releasing two more studio albums and a live album through Epitaph between 1998 and 2001 with singer Chad Price.  "Cool to Be You" was recorded with Aukerman in 2002, but its release was delayed until 2004.  The band switched from Epitaph to Fat Wreck Chords partly due to the enthusiasm of label head Fat Mike, who cited the Descendents as one of his favorite bands.  "Cool to Be You" became the fourth Descendents release to chart, reaching #143 on the "Billboard" 200 and #6 amongst independent albums.

Descendents: The Descendents are a punk rock band formed in 1977 in Manhattan Beach, California by guitarist Frank Navetta, bassist Tony Lombardo and drummer Bill Stevenson.  In 1980, they enlisted Stevenson's school friend Milo Aukerman as a singer, and reappeared as a punk rock band, becoming a major player in the hardcore punk scene developing in Los Angeles at the time.  They have released seven studio albums, three live albums, three compilation albums, and three EPs.  Since 1986, the band's lineup has consisted of singer Milo Aukerman, guitarist Stephen Egerton, bassist Karl Alvarez, and drummer Bill Stevenson.

Bill Stevenson (musician): John William "Bill" Stevenson (born September 10, 1963) is an American musician and record producer.  He is the drummer, main songwriter, and the only constant for the California punk rock group Descendents since its inception.  In late December 1981 he played a few concerts with Black Flag because their drummer ROBO was detained in England after a tour there.  He went on to record with Black Flag on several of their albums until 1985.  After this he focused his attention on Descendents and played with them until Milo Aukerman left in 1987.  After Milo had left, Bill and the others from Descendents, Karl Alvarez and Stephen Egerton, got singer Dave Smalley of Dag Nasty and formed All.  All went on to have two more singers, Scott Reynolds (1989–1993) and Chad Price (1993–present).  Aukerman came back to do the 1996 album "Everything Sucks", the 2004 album "Cool to Be You" and the newest, 2016's "Hypercaffium Spazzinate".  All and Descendents continue to tour between Stevenson's and Aukerman's respective careers as a recording engineer and a biochemist.

Filmage: Filmage: The Story of Descendents/All is a 2013 independent documentary film chronicling the history of the American punk rock bands the Descendents and All.  It was written by Matt Riggle, who produced and directed it with Deedle LaCour.  The film uses an oral history format, telling the bands' stories through the use of interviews with over 40 subjects, as well as new and archival footage.  It stars drummer Bill Stevenson, singer Milo Aukerman, bassist Karl Alvarez, and guitarist Stephen Egerton, and features nearly all past and present members of both bands.  "Filmage" also features numerous musicians who were contemporaries of, worked with, or were influenced by the Descendents and All.

Milo Goes to College: Milo Goes to College is the first full-length album by the American punk rock band the Descendents, released in 1982 through New Alliance Records.  Its title referred to singer Milo Aukerman's decision to leave the band to attend college, and its cover illustration introduced a caricature of him that would go on to become the band's mascot.  It was the Descendents' last record with founding guitarist Frank Navetta, who quit the band during the hiatus that followed its release.

Koshi Inaba: Koshi Inaba (稲葉浩志 , Inaba Kōshi ) , born Hiroshi Inaba (稲葉浩志 , Inaba Hiroshi ) on September 23, 1964 in Tsuyama, Okayama, is a Japanese vocalist, multi-instrumentalist and songwriter.

Milo Aukerman: Milo Jay Aukerman, Ph.D (born January 1, 1963) is an American vocalist, songwriter, and former research biochemist.  Aukerman is most widely known for being the lead singer of the punk rock band the Descendents, a group widely considered to be pioneers of "pop punk".  A caricature of Aukerman serves as the band's mascot.

Ride the Wild / It's a Hectic World: "Ride the Wild" / "It's a Hectic World" is the 1979 debut single by the American punk rock band the Descendents.  It was the band's first release and displayed a new wave and surf sound.  It was recorded at a time when the band lacked a lead singer, so vocals on the recording were provided by guitarist Frank Navetta and bassist Tony Lombardo.  With the addition of singer Milo Aukerman in 1980, the band moved towards a hardcore punk sound.  "Ride the Wild" and "It's a Hectic World" were re-released in later years on compilation albums.

B'z: B'z (ビーズ , Bīzu ) is a Japanese rock duo, consisting of guitarist, composer and producer Takahiro "Tak" Matsumoto (松本 孝弘 , Matsumoto Takahiro ) and vocalist and lyricist Koshi Inaba (稲葉 浩志 , Inaba Kōshi ) , known for their energetic hard-rock tracks and pop ballads.

Everything Sucks (Descendents album): Everything Sucks is the fifth studio album by American punk rock band the Descendents, released in 1996 through Epitaph Records.  It was their first album of new studio material since 1987's "All", after which singer Milo Aukerman had left the band to pursue a career in biochemistry.  The remaining members (bassist Karl Alvarez, guitarist Stephen Egerton, and drummer Bill Stevenson) had changed the band's name to All and released eight albums between 1988 and 1995 with singers Dave Smalley, Scott Reynolds, and Chad Price.  When Aukerman decided to return to music the group chose to operate as two acts simultaneously, playing with Aukerman as the Descendents and with Price as All.

Supporting paragraphs: Milo Aukerman Koshi Inaba
Answer: vocalist