To capture the breadth of reactions seen, here we focus on two representative classes of cancer drugs: (1) epidermal growth factor receptor (EGFR) inhibitors, which are widely used by most oncologists for specific malignancies harboring EGFR mutations, have been in practice for over 15 years, and, therefore, have well-established side-effect profiles; and (2) immune checkpoint inhibitors, which are relatively new, having first gained US Food and Drug Administration (FDA) approval in late 2014 and, therefore, have significantly less data available on their emerging side-effect profiles. Here, EGFR is linked to cancer.