Hi, if it is not present in PDB, then you have to model it. However, strictly speaking of IL-1b, half of its structure is available in PDB;

Article Disordered water within a hydrophobic protein cavity visuali...

The rest you can model based on sequence homology etc.

In the UniProt entry (https://www.uniprot.org/uniprot/P01584#structure) you can even find AlphaFold generated models, though, they are sometimes not very accurate, they can give you an idea.

Don't forget the AlphaFold structural prediction data base (and associated tools), https://www.alphafold.ebi.ac.uk/