Meanwhile, among COVID-19 patients without cancer, univariate analysis showed that red blood cell count, white blood cell count, lymphocyte count, neutrophil count, lactate dehydrogenase, CK-MB, troponin I, fibrinogen, D-dimer, IL-6, TNF-α, IL-4, IL-2, and CD4/CD8 ratio may be factors affecting the severity of COVID-19 (Supplementary Table S1). Here, IL2 is linked to COVID-19.