However, the recent unraveling of specific SCLC categories led to the discovery of SCLC-I, with higher PD-L1 expression, as well as higher expression of other targetable immune checkpoints such as CD80/86, ICOS, TIGIT, TIM3, and LAG3, all of which have been shown to predict improved CPI-induced outcomes [17]. The gene discussed is ICOS; the disease is small cell lung carcinoma.