PDCD1 and melanoma: To ensure that the observed PD-1 agonist activity in a cell-bound state was not unique to the PPI15–24 TCR targeting moiety, IgV–PD-L1 and CA949 were each fused to an alternate affinity-enhanced TCR specific for gp100280–288 (HLA-A*02:01, YLEPGPVTA), a melanoma epitope (30).