The canonical neural-net predictor of peptide–HLA binding — the tool you'll see cited as the baseline almost everywhere in this field.

NetMHCpan is a neural network that, given a peptide and an HLA allele, predicts how likely the peptide is to bind and be presented. Its "pan" design generalizes across alleles — including rare ones with little data — by learning from the alleles' sequences. MHCflurry is a popular open-source counterpart.
It matters as a benchmark for what's already solved: HLA-binding prediction is the mature, commoditized step, and beating NetMHCpan on binding alone is hard, so it's a weak basis for differentiation. That's exactly why the value — and the investment thesis — has moved up the stack to processing, presentation, and especially immunogenicity, where predictors are still weak and the headroom is large.
Neither is uniformly better. NetMHCpan-4.1 tends to lead on naturally-processed/presented peptides and rare-allele coverage thanks to its pan-allele design; MHCflurry is open-source, considerably faster, and competitive on non-9-mer peptides. Many pipelines run both and combine the scores rather than choosing one.
Binding-affinity prediction is trained on lab-measured peptide–HLA binding strength. Eluted-ligand prediction is trained on peptides actually found presented on cells by mass spectrometry, so it captures the full antigen-processing pathway, not just binding. Modern predictors like NetMHCpan-4.1 output both; the EL score is usually the better presentation signal.
Because HLA-binding prediction is already a mature, commoditized step where NetMHCpan is a strong baseline. The unsolved, high-value problem is immunogenicity — predicting which presented peptides actually trigger a T-cell response — which is where current AI research and investment are concentrated.