trigger updateOppTeamMember on Resource_Request__c (after insert, after update) {
    // Write trigger on RR for insert and update triiger event
    List<id> OppoIdList = new List<id>();
    // create list of Oportunity
    map<id, id> OppoRRMap = new map<id,id>();
    // Create map for RR Id and its associated Opportunity ID
    map<id, Resource_Request__c> ResourceRequestMap = new map<id, Resource_Request__c>();
    // Create map for RR Id and Its associated RR Object
    for(Resource_Request__c rr : trigger.new){
    // Itterate Over RR
        OppoIdList.add(rr.Opportunity__c);
    // Add RR OpporutunityID to its associated Opportunity
        OppoRRMap.put(rr.Id, rr.Opportunity__c);
    // Put RR Id and its associated RR Opportunity Id to OppoRRMap 
        ResourceRequestMap.put(rr.Id, rr);
    // Put RR id and its associated RR object to ResourceRequestMap
    }
    
    List<OpportunityTeamMember> otmListForDelete= new List<OpportunityTeamMember>();
    List<OpportunityTeamMember> otmListForInsert= new List<OpportunityTeamMember>();
    
    
    List<OpportunityTeamMember> otmList = [Select Id, OpportunityId ,TeamMemberRole, User.Name From OpportunityTeamMember Where OpportunityId In:OppoIdList ];
    
    system.debug('--OppoIdList--'+OppoIdList);
    system.debug('--otmList --'+otmList );
    //Create List of OTM from fire a query on OTm where id is from OppoIdList
    map<id, List<OpportunityTeamMember>> OppoOtmMap = new map<id, List<OpportunityTeamMember>>();
    // Create map for Opportunity id and list of its associated OTM
    for(OpportunityTeamMember otm : otmList){
    // Itterate OTm with OtmList
        List<OpportunityTeamMember> tempList = OppoOtmMap.get(otm.OpportunityId);
    // get OTM Opportunty id from OppoOtmMap and store in tempList
        if(tempList!= null && tempList.size()>0){
    // Now we have to store OTM in templist if they are one or more or there are not in OTM 
           tempList.add(otm);   
    // if already one than add it        
        } else{
                tempList = new List<OpportunityTeamMember>();
     // If new than create new list
                tempList.add(otm);
     // Than add OTM in tempList    
        }
        OppoOtmMap.put(otm.OpportunityId, tempList);
      // Now we have templist with OTM, Put OTM ID and its associated OtmList in OppoOtmMap
    }
        for(Resource_Request__c RR : trigger.new){

        Boolean flag =false;
        Resource_Request__c oldRR = null;
        
        system.debug('--oldMap--' +Trigger.oldMap);
        system.debug('--rr.id--' +rr.id);
        if(Trigger.oldMap != null){
        
          oldRR = Trigger.oldMap.get(rr.id);
         }
        
        system.debug('--OldRR--'+OldRR);
        system.debug('--rr.Opportunity__c--'+rr.Opportunity__c);
        system.debug('--OppoOtmMap--'+OppoOtmMap);
        List<OpportunityTeamMember> tempList1 = OppoOtmMap.get(rr.Opportunity__c);
        system.debug('--tempList1 --'+tempList1 );

            if(tempList1 != null){
                system.debug('--tempList1 --'+tempList1 );
                for(OpportunityTeamMember otm : tempList1 ){
                    if(otm.userId== oldRR.CRM_AssignedTeam__c || otm.userId== oldRR.Analyst_Contractor_lookup__c || otm.userId== oldRR.BD_Partner__c || otm.userId== oldRR.Delivery_Consultant__c || otm.userId== oldRR.HAT_Support__c || otm.userId== oldRR.Legal_Proposal_Support_assigned__c || otm.userId== oldRR.Presentation_QA_Assigned__c){
                   
                   
                            otmListForDelete.add(otm);
                            system.debug('--otmListForDelete--'+otmListForDelete);
                    }
                  }
                }   

            if(tempList1 != null){
            for(OpportunityTeamMember otm : tempList1 ){
            if(rr.CRM_AssignedTeam__c== otm.userId){
                        flag = true;
                    }
                }
            }
        
            if(flag == true){
            // if flag is true then nothing will happen
                
            } else{
            // if flag is not true new OTM will be added
                    OpportunityTeamMember otm1 = new OpportunityTeamMember();
                    otm1.userId = rr.CRM_AssignedTeam__c;
                    otm1.TeamMemberRole= 'Sr. Client Insights Manager';
                    otm1.OpportunityId = rr.Opportunity__c;
                    otmListForInsert.add(otm1);                    
            // add New OTM to otmList
            }
       }       
       

    
    if(otmListForInsert.size()>0){

        insert otmListForInsert;
    }
    
    if(otmListForDelete.size()>0){

        delete otmListForDelete;

    }
    
     }
Hear is an answer
Thanx for not given any answer