Look up values from two different table basis filter conditions

minaxi Please try below steps:

Step 1 : Add a calculated column in CampaignMember Table as below

LeadContactID = IF(Test70CampaignMember[Lead ID]=BLANK(),Test70CampaignMember[ContactID],Test70CampaignMember[Lead ID] )

It will be now as below:

Step 2 : Merge both Lead and Contact table using either Power Query or DAX. In this case, I've used DAX to create a new table as below

Test70LeadContact = UNION(Test70Lead,Test70Contact) 

Note - I've renamed the first field as ID (to be generic)

Step 3: Please check and ensure now the relationship looks as below:

That's it !! Now you simple drag the corresponding fields as required and the expected output will be as below

Hi minaxi,

Establish a relationship between 'Campaign' and 'Campaign Member'. Create below measures:

Lead/ContactID =
IF (
    SELECTEDVALUE ( 'Campaign Member'[Type] ) = "Lead",
    SELECTEDVALUE ( 'Campaign Member'[Lead ID] ),
    SELECTEDVALUE ( 'Campaign Member'[ContactID] )
)

First Name =
IF (
    SELECTEDVALUE ( 'Campaign Member'[Type] ) = "Lead",
    CALCULATE (
        SELECTEDVALUE ( 'Lead'[First Name] ),
        FILTER ( 'Lead', 'Lead'[LeadID] = [Lead/ContactID] )
    ),
    CALCULATE (
        SELECTEDVALUE ( 'Contact'[FirstName] ),
        FILTER ( 'Contact', 'Contact'[ContactID] = [Lead/ContactID] )
    )
)

Last Name =
IF (
    SELECTEDVALUE ( 'Campaign Member'[Type] ) = "Lead",
    CALCULATE (
        SELECTEDVALUE ( 'Lead'[LastName] ),
        FILTER ( 'Lead', 'Lead'[LeadID] = [Lead/ContactID] )
    ),
    CALCULATE (
        SELECTEDVALUE ( 'Contact'[LastName] ),
        FILTER ( 'Contact', 'Contact'[ContactID] = [Lead/ContactID] )
    )
)

Add corresponding fields and above measures into a Table visual.

Best regards,

Yuliana Gu