This timeline highlights various milestones in understanding the JAK-STAT pathway since 1984. GAS, gamma activated sequence; IFN, interferon; ISGs, IFN stimulated genes, ISRE, interferon-sensitive response element; SCID, severe combined immune deficiency; KO, knockout; SLE, systemic lupus erythematosus; PK, pseudokinase; MPN, myeloproliferative neoplasms; GOF, gain-of-function; SOCS, suppressor of cytokine signaling; PIAS, protein inhibitor of activated STAT, Tum-l, tumorous lethal.