Medical cannabis is legal in PA, however the medical program has not yet been implemented. For a quick overview of the program, please visit https://norml.org/pa/item/pennsylvania-medical-marijuana-law
For a more in-depth look at how to become a medical cannabis patient in PA once the program is implemented, please visit PA’s Department of Health website here: https://www.health.pa.gov/My%20Health/Diseases%20and%20Conditions/M-P/MedicalMarijuana/Pages/Patients-Caregivers.aspx#.WKoOHBIrKuU
Note, that it is currently illegal to mail and/or ship cannabis products across state lines. If you will be visiting a legal state, such as CA, you are eligible to obtain a CA medical cannabis recommendation and purchase cannabis products from a CA dispensary whilst you are in the state.