Collagen develops resistance to programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) immunotherapy in lung tumors through up-regulation of LAI R1 expression and downstream signaling, and reduction of tumor collagen deposition through lysyl oxidase like 2 (LOXL2) inhibition increases T cell infiltration, reduces depletion of T cells, and eliminates resistance against PD-1/PD-L1 (72). Here, PDCD1 is linked to neoplasm.