Moreover, increased expression of the immune checkpoint proteins, PD‐1 (CD279) and TIM‐3 (CD366), on CD8+ T cells was detected in severe and critical COVID‐19 patients (Diao et al., 2020; Y. Zhou, Fu, et al., 2020), suggesting that T cell exhaustion may occur. The gene discussed is HAVCR2; the disease is COVID-19.