@rfriend50 Hi and yes im on Medicare both a and b but I also am retired military and have a supplement called Tricare for Life. The Meds are covered thru Tricare via a program called express scrip. I just started getting my meds thru them and have not needed my one immunosuppressive yet Tacrolimus. So im not sure if Medicare itself covers immunosuppressants.
Also tho like @azdan99 mentioned if you have had any military time you may be able to get them thru the VA.
I hope that helps
Have a Blessed Day