Fig 2: Immunohistochemical positive control (original magnification × 400). a Programmed cell death protein 1 receptor (PD-1): lymph node (germinal center in follicle). b Programmed cell death protein 1 receptor ligand (PD-L1): skeletal muscle. c PD-L2: lymph node (subcapsular sinus)

Fig 3: Changes in the targets for PD-1 according to the epoch. (A) Pie charts showing the consistent target of PD-L1; (B) pie charts presenting the changes of other targets concurrently used with PD-L1; and (C) pie charts showing the changes of antibody clones of PD-L1. PD-1, programmed cell death protein-1; PD-L1, programmed death ligand-1; PD-L2, programmed death ligand-2.

Fig 4: Targets of PD-1 axis and antibody clones for PD-L1. (A) Pie charts showing the target of PD-L1; (B) pie charts presenting other targets concurrently used with PD-L1; and (C) pie charts showing the antibody clones of PD-L1. PD-1, programmed cell death protein-1; PD-L1, programmed death ligand-1; PD-L2, programmed death ligand-2.