ICIs have shown promise as a therapeutic approach in SMARCA-altered cancers such as SMARCA4-deficient thoracic sarcoma, SMARCA4-altered non-small-cell lung cancer (NSCLC), and small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) [21,44,45]. Here, SMARCA4 is linked to ovarian small cell carcinoma.