The degree of cancer risk appears to vary with the selectivity of the JAK-I; pan-JAK inhibitors, such as tofacitinib, which target multiple JAK isoforms (JAK1, JAK2, JAK3, and TYK2), may potentially modulate a wider spectrum of molecular signaling pathways compared to more selective inhibitors like filgotinib and upadacitinib, which predominantly target JAK1 [17,34]. Here, JAK1 is linked to cancer.