INS and COVID-19: Pulmonary therapy is becoming more patient-compliant due to minimal invasiveness and economic benefits following the scientific and technological advances in DPIs formulations (e.g., Exubera®, Technosphere® insulin, AIR® insulin, Afrezza®, Inbrija®, Adasuve®, Levadex®, CVT427, possible COVID-19 drugs, and vaccines...etc).