JAK3 is a non-receptor protein tyrosine kinase involved in the interferon-alpha/beta/gamma pathway and is a member of the JAK/STAT signaling pathway. The JAK3 V722I variant has been reported as a likely benign germline polymorphism (ClinVar, https://preview.ncbi.nlm.nih.gov/clinvar/variation/134573/) and also as an acquired somatic variant in some tumors. It has been reported to be an activating variant of JAK3 and initial in vitro studies suggest that this variant may play a role in the regulation of PD-L1 expression. Also, V722I resulted in constitutive phosphorylation of Jak3 and was transforming in cell culture. Clinical correlation is recommended.