If you are asking about a Federal return and the business code on a quick NAICS search I just did turns up 4 business codes with the subject of marijuana. I'll provide the links below for your perusal.
111998 "Marijuana, grown in an open field" is under "all other miscellaneous crop farming."
https://www.census.gov/cgi-bin/sssd/naics/naicsrch?code=111998&search=2017%20NAICS%20Search
111419 "Marijuana, grown under cover" (glass or protective cover.)
https://www.census.gov/cgi-bin/sssd/naics/naicsrch?code=111419&search=2017%20NAICS%20Search
424590 "Marijuana merchant wholesalers" under "Other Farm Product Raw Material Merchant Wholesalers"
https://www.census.gov/cgi-bin/sssd/naics/naicsrch?code=424590&search=2017%20NAICS%20Search
453998 "Marijuana stores, medical or recreation" under "All other miscellaneous store retailers."
https://www.census.gov/cgi-bin/sssd/naics/naicsrch?code=453998&search=2017%20NAICS%20Search
