The markers programmed cell death 1 (PD-1), TIGIT, TIM3, and programmed cell death ligand 1 (PD-L1) are traditionally thought to be exhaustion markers upregulated during chronic antigen exposure but have also been shown to have increased expression in several acute infections, including COVID-19 (6, 42, 43). This evidence concerns the gene HAVCR2 and COVID-19.