From his campaign site:

As your Governor, I will work with members of the Indiana General Assembly to decriminalize both medical and recreational marijuana.

Military veterans and others who suffer from psychological, emotional, and physical pain should not be denied a proven, viable alternative to highly-addictive narcotics.  Medicinal marijuana has been proven to effectively aid cancer patients in managing the many side effects of chemotherapy and other treatments.

Anyone who has been convicted of a marijuana-related, non-violent drug offense should have their sentenced commuted immediately and their conviction should be expunged.

If beer, wine, and liquor are legal for adult recreational consumption, so should all forms of cannabis. 2020 campaign site.