Medical overlaps---how do they keep it all straight?

The insurance company has approved the treatment plan with Keytruda and it all starts tomorrow. I met with my internist and her pharmacist yesterday to look at what meds I have been on for my Diabetes II plan. A couple of the oral meds have potential conflicts with the cancer treatment and observation scans. So out with two oral meds and onto an injectable insulin. The treatment for the cancer can cause blood sugar spikes so hopefully the injectable insulin dosage can be modified on a short notice to respond to any spikes. I am constantly amazed at how the doctors/staff can look at such complicated situations and make sense of a treatment plan. Thank God for smart doctors!