Moreover, the risk factors for progression to severe illness in COVID-19 patients with cancer not only included the previous variables of older age, interleukin 6, procalcitonin, D-dimer, and lymphocytes but also included tumour stage, tumour necrosis factor α, N-terminal pro-B-type natriuretic peptide, CD4+ T cells and albumin–globulin ratio [12, 13, 30]. Here, CD4 is linked to cancer.