A method of identifying an inhibitory chimeric antigen receptor (iCAR) or protective chimeric antigen receptor (pCAR)/activating chimeric antigen receptor (aCAR) target pair comprising: i) selecting an iCAR or a pCAR capable of preventing or attenuating undesired activation of an effector immune cell, wherein the iCAR or pCAR target is directed to a target extracellular polymorphic epitope from a gene selected from the group consisting of the 598 genes listed in Fig. 22; and ii) selecting an aCAR capable of inducing activation of an effector immune cell, wherein the aCAR is directed to a target non-polymorphic cell surface epitope of a protein selected from the group consisting of the 49 target proteins listed Fig. 23; iii) expressing the iCAR or pCAR from step i) and the aCAR from step ii) in a population of cells; iv) subjecting the population of cells to one or more assays, wherein the one or more assays are capable of detecting preventing or attenuating undesired activation of an effector immune cell and/or detecting inducing activation of an effector immune cell; and v) identifying an iCAR or pCAR/aCAR target pair based on the assay results in step iv), wherein the target gene for the iCAR or pCAR is located in a chromosomal region that exhibits loss of heterozygosity in tumor cells and wherein the LOH position is selected from the group consisting of a substitution, deletion, and insertion, wherein the LOH position is a SNP wherein the SNP is determined as a suitable iCAR or pCAR target based on an LOH candidate score, and wherein the score consists of the product of the percentile rank of each of the following: a) proportion of tumors with LOH at that SNP; b) prevalence of the SNP allele; c) ratio of the standard deviation of expression values across tissues to the median; and d) whether or not there is a tumor suppressor gene on the chromosome. i) selecting an iCAR or a pCAR capable of preventing or attenuating undesired activation of an effector immune cell, wherein the iCAR or pCAR target is directed to a target extracellular polymorphic epitope from a gene selected from the group consisting of the 598 genes listed in Fig. 22; and ii) selecting an aCAR capable of inducing activation of an effector immune cell, wherein the aCAR is directed to a target non-polymorphic cell surface epitope of a protein selected from the group consisting of the 49 target proteins listed Fig. 23; iii) expressing the iCAR or pCAR from step i) and the aCAR from step ii) in a population of cells; iv) subjecting the population of cells to one or more assays, wherein the one or more assays are capable of detecting preventing or attenuating undesired activation of an effector immune cell and/or detecting inducing activation of an effector immune cell; and v) identifying an iCAR or pCAR/aCAR target pair based on the assay results in step iv), wherein the target gene for the iCAR or pCAR is located in a chromosomal region that exhibits loss of heterozygosity in tumor cells and wherein the LOH position is selected from the group consisting of a substitution, deletion, and insertion, a) proportion of tumors with LOH at that SNP; b) prevalence of the SNP allele; c) ratio of the standard deviation of expression values across tissues to the median; and d) whether or not there is a tumor suppressor gene on the chromosome.