A Chinese study further investigated the relationship between soluble checkpoint molecules and COVID-19 progression, reporting higher concentrations of 11 molecules (sGITR, s4-1BB, sTIM-3, sCD27, sLAG-3, sPD-1, sCD28, sCTLA-4, sBTLA, sHVEM, and sCD80) in critical patients than in moderate cases. This evidence concerns the gene HOXD13 and COVID-19.