It really depends. Providing they accept you as a special circumstances case, they'll base your overall grade on the paper that you do actually sit (assuming you're able to sit one), but that doesn't necessarily mean you'll get the same grade as the paper you take.
Last year my eldest son took Paper 1 of IGCSE Computer Science but he then contracted covid and couldn't take Paper 2.
He achieved grade 6 on the paper he took, but he was awarded a grade 5 overall as his final IGCSE grade.