ICOS and melanoma: Additionally, the potential value of various new inhibitory immune checkpoints (BTLA [130–132], B7 family [133–137], IDO-1 [138, 139], LAG-3 [140, 141]) and costimulatory molecules (GITR [142–145], ICOS [146–148], OX40 [149–151], 4-1BB [152–154], CD40 [155, 156], CD27 [157–159]) has been confirmed for melanoma treatments.