IL6 and lung carcinoma: To determine the possibility of JAK/STAT signalling inhibition, we measured L971 effects on the constitutive STAT3 phosphorylation in lung cancer cell line A549 (Figure 1F) and cervical cancer cell line HeLa (Figure S1A), as well as IL6‐induced STAT3 phosphorylation in HeLa cells (Figure S1B), indicating L971 inhibited STAT3 activation regardless of different genetic backgrounds, so did the FDA approved JAK inhibitors such as Ruxolitinib,29 Baricitinib30 and Tofacitinib31 (Figure S1C,D).