Thanks.. I am facing issue while using runApex Open CTI Method.. Below Is the code : 

OpenCTIComp.cmp :- 

<aura:component implements="force:appHostable,flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId,forceCommunity:availableForAllPageTypes,force:lightningQuickAction" access="global" >
    <ltng:require scripts="https://elision-dev-ed.lightning.force.com/support/api/50.0/lightning/opencti_min.js"/>
    <ltng:require scripts="https://elision-dev-ed.lightning.force.com/support/api/49.0/interaction.js"/>
    
    <lightning:button variant="brand" class="slds-col slds-size_3-of-12 button-color"
                    label="Call RunApex" onclick="{!c.callingApex}"/>
    
    <lightning:button variant="brand" class="slds-col slds-size_3-of-12 button-color"
                    label="Soft Phone Panel" onclick="{!c.callingSoftPanel}"/>
     
    <lightning:button variant="brand" class="slds-col slds-size_3-of-12 button-color"
                    label="Open Call Centre Setting" onclick="{!c.openCallSetting}"/>
    
</aura:component>

OpenCTIComp.controller :- 

 callingApex : function(component, event, helper) {
        debugger;
        console.log('in onInit');
        
        var callback = function(response) {
            debugger;
            if (response.success) {
                console.log('API method call executed successfully! returnValue:', response.returnValue);
            } else {
                console.error('Something went wrong! Errors:', response.errors);
            }
        };
        
        var param = {apexClass: 'DialShreeApi', methodName: 'fetchLead', methodParams: 'phoneNumber=+919428808249'};
        param.callback = callback;
        //Invokes API method
        sforce.opencti.runApex(param);
        
        sforce.opencti.runApex({
            apexClass : 'DialShreeApi',
            methodName : 'fetchLead',
            methodParams : 'phoneNumber=+919428808249',
            callback : function(result) {
                debugger
                if (result.success) {
                    alert('setSoftphonePanelHeight is successfully executed.');
                    var retVal = result.returnValue;
                    
                    var returnJSON = JSON.parse(retVal); // parse the string into an object
                    console.log(returnJSON);
                    
                    if ( returnJSON.status == "ringing")
                    {
                        console.log('This is taking the retun value as ringing');
                        //set the label to Dialing and dont start the time!
                    }
                    
                } else {
                    alert('setSoftphonePanelHeight is successfully executed.');
                    throw new Error('Unable to make a call. Contact your admin.');
                }
            }
        });
    }

Apex Class :- 
    @AuraEnabled
    public static String fetchLead(String phoneNumber) {         
        
        List<contact> conList = New List<contact>();
        List<Lead> leadList = New List<Lead>();
        Set<Id> leadConIdSet = new Set<ID>();
        System.debug('**phoneNumber***'+phoneNumber);
        if(phoneNumber.length() > 2){
            String status = 'Closed - Converted';
            String searchQuery = 'FIND \'' + phoneNumber + '\' IN ALL FIELDS RETURNING  Lead(Id,Phone where status != \'' +status+ '\'), Contact(Id,Phone)';
            system.debug(searchQuery);
            List<List <sObject>> searchList = search.query(searchQuery);
            System.debug('@@searchList=='+ searchList);
            leadList = ((List<Lead>)searchList[0]);
            conList  = ((List<contact>)searchList[1]);
            System.debug('***searchList***'+searchList.size());
            System.debug('***leadList***'+leadList);
            System.debug('***conList***'+conList);
            
            if(conList.size() != 0) {
                for(Contact con : conList) {
                    leadConIdSet.add(con.Id);
                }
            }else if(leadList.size() !=0){
                for(Lead ld : leadList) {
                    leadConIdSet.add(ld.Id);
                }
            }
            else {
                leadConIdSet = new Set<ID>();
            }
        }
        System.debug('JSON:--'+leadConIdSet);  
        return JSON.serialize(leadConIdSet);
    }

I am facing issue that i am not able to get response in callback function used for runApex method. And even after apex method runs successfully i am not able to get console in front end.