Oncologists run the risk of misjudging the effectiveness of immune checkpoint inhibitors (ICIs) in cancer treatment if they do not account for patients' immune system-affecting medications.[1] These drugs can cause confounding effects that prevent optimal results from therapy.[1] The article calls for mandatory consideration of the full list of drugs before prescribing cancer immunotherapy.[1] Misinterpretation of ICI activity leads to the loss of the chance for the best treatment.[1] Immunotherapeutic approaches include immune checkpoint inhibitors.[1] Biologic therapy is effective in more than 60% of patients with rheumatic diseases where standard therapy has failed.[1] Tumor necrosis factor (TNF) inhibitors are currently used.[1]